Nippostrongylus brasiliensis infection in the rat: 2. A comparison of production of antibodies in bile and serum by baby rats,lactating rats and adult rats

Production of bile lgA and serum lgG antibody responses against whole worm antigens and worm metabolic product antigens occurred by 7 to 14 days after a single infection with $\text{N. brasiliensis}$ and was similar in adult rats, lactating rats and baby rats. Production of bile lgA antibodies against phosphorylcholine was greater in adult rats, 7 days after infection, than in baby rats or lactating rats. lgA antibody production by baby rats may be affected by immaturity of the intestinal lgA system, and diversion to the mammary gland of lgA-plasma cell precursors may occur in lactating rats. Such effects may be involved in the failure of baby rats and lactating rats to expel parasites by day 21 at which time in adult rats expulsion was complete.     

Solid-phase enzyme immunoassay of bovine antibody responses following immunization against and natural infection with Pasteurella haemolytica

A solid-phase enzyme immunoassay (EIA) was developed in order to monitor bovine antibody responses following immunization against and natural infection with $\text{Pasteurella haemolytica}$ serotype A:1. Non-ionic surfactants, used in many antibody EIAs to reduce non-specific immunoglobulin binding, had to be avoided because they inhibited specific binding of bovine antibodies to $\text{P. haemolytica}$ antigens. Calves were immunized with a KSCN extract of $\text{P. haemolytica}$. Subcutaneously immunized animals developed a significantly higher humoral antibody response than did intranasally vaccinated animals. Intranasally immunized calves developed a slightly, but not significantly higher nasal antibody response than did calves vaccinated subcutaneously. Field study results based on bacterial isolation and EIA detection of antibodies to $\text{P. haemolytica}$ indicate that cattle can generate carrier states where bacteria are present in the upper respiratory tract, yet no humoral antibody response is induced. The converse was also found where cattle were free from $\text{P. haemolytica}$ in the upper respiratory tract, yet possessed a good humoral antibody response to $\text{P. haemolytica}$.     

The role of serum and biliary antibodies and cell-mediated immunity in the clearance of S. typhimurium from chickens

The development of three parameters of immunity in response to a non-lethal infection of $\text{Salmonella typhimurium}$ in adult chickens has been examined. Intravenous inoculation of 1 × 10⁶ organisms established infection in the liver, spleen and intestinal tract of all birds; the organism persisted in these sites until day 9 of the infection, after which it was cleared rapidly from all sites. High levels of agglutinating and haemagglutinating antibodies were found in serum and bile 5 days after infection; they peaked at days 7 to 10, and detectable antibody was still present in both fluids 6 weeks after infection. The presence of this antibody did not appear to cause a significant reduction in organism numbers in any of the sites examined. Cell mediated immunity was detected at day 14. It is suggested that cell mediated immunity is responsible for clearance of the organisms from the tissues.     

Local antibody responses in the bile and faeces of sheep infected with Fasciola hepatica

The effect of infection with the liver fluke Fasciola hepatica on serum, bile and faecal immunoglobulin and antibody levels was studied in Scottish Blackface sheep. In the serum the immunoglobulins showing the most marked increase were IgG1 and IgG2 and their maximal values were reached at 16 weeks after infection. In the bile IgG2 rose to peak values at two weeks and IgG1, IgA and IgM were maximal at four weeks after infection. The levels of faecal IgG and IgA were low after primary infection but after reinfection a rapid increase in IgA concentration was observed within one to two weeks. Haemagglutinating antibody levels against egg antigens, juvenile and adult excretory-secretory antigens and adult fluke somatic antigens were evaluated. In the sera high titres were observed starting from two to four weeks after infection and persisting until 14 to 16 weeks. Bile haemagglutinating antibodies against excretory-secretory antigens showed the highest level at two and four weeks after infection while antibodies against adult somatic antigens reached maximal titres between four and eight weeks. Faecal antibody levels after primary infection were low but increased rapidly within two weeks after reinfection, coinciding with the elevation in faecal IgA concentration. However, there was no reduction in the number of flukes established in reinfected animals.     

Thymus atrophy during early pregnancy and its effect on a Trichinella spiralis infection in mice,including intestinal pathology and blood eosinophilia

The effects of pregnancy on the course of a $\text{Trichinella spiralis}$ infection and associated histopathological changes in thymus and small intestine were studied in outbred Swiss mice. For this purpose pregnant mice were orally infected with $\text{T. spiralis}$ on various days (1 to 8) $\text{post coitum}$. Virgin, age-matched infected and non-infected mice served as controls.Pregnancy induced a severe but reversible thymus atrophy, which was even more marked during a $\text{T. spiralis}$ infection. Thymus atrophy was most dramatic during mid and late pregnancy. During the involution phase a distinct increase in mast cells was observed.In animals infected during early pregnancy a not statistically significant inhibitory effect on worm expulsion was observed, whereas no effect was seen on the yield of muscle larvae, small intestine pathology (numbers of eosinophils, intestinal mast cells and globule leucocytes), blood eosinophilia and antibody production.Infection given during mid-pregnancy exerted an inhibitory effect on blood eosinophilia.On the basis of these results, it is concluded that although a severe atrophy of the thymus occurs during mid and late pregnancy, no effect on worm expulsion and intestinal pathology was observed when the infectious agent was given before thymus depletion started.     

Lack of reactivity of sera from Theileriaparva-infected and recovered cattle against cell membrane antigens of Theileria parva transformed cell lines

Sera from $\text{Theileria}$$\text{parva}$ infected, recovered and rechallenged cattle were tested in complement-dependent cytotoxicity, membrane immunofluorescence and antibody-dependent cellular cytotoxicity assays for the presence of antibodies against cell membrane antigens of $\text{T}$. $\text{parva}$ transformed cell lines.In the complement-dependent antibody-mediated cytotoxicity assay, sera from lethally infected animals were negative. Some recovered cattle showed a positive reaction, but such reactions were also observed when an eland cell line infected with $\text{T}$. $\text{taurotragi}$, and bovine lymphoblastoid cells were used as targets. Reaction was less against Ig-negative peripheral blood lymphocytes.Evidence is presented that these reactions could be evoked by attachment of immune complexes to Fc-receptors. It is concluded that cattle exposed to $\text{T}$. $\text{parva}$ infection do not develop antibodies against specific $\text{T}$. $\text{parva}$ (or $\text{T}$. $\text{parva}$-induced) cell surface antigens.     

The antibody response to bovine lymphocyte alloantigens

Antibodies were raised against lymphocyte cell-surface antigens by multiple immunisations with purified lymphocytes or by the exchange of skin allografts. Eighteen of 21 cattle immunised with lymphocytes raised a detectable cytotoxic antibody response. The serum antibody from 10 responders recognized only common lymphocyte antigens, those antigens which are present on all peripheral blood lymphocytes. One animal responded only to B lymphocyte antigens while 7 others responded to both classes of antigens. The amount of antibody produced varied greatly between individuals; antibody titres ranged from 1 to 1028. Antibody raised early in the response was sensitive to treatment with 2-mercaptoethanol (2-ME) suggesting that IgM was the predominant class of immunoglobulin. Subsequently antibody became resistant to this treatment suggesting the appearance of IgG. The antibody responses following the exchange of skin grafts were very similar in all 12 cattle studied. High titred antibody to common lymphocyte antigens was detected in the serum 14 days after grafting. The early antibody activity was sensitive to 2-ME treatment but became totally resistant within 14 days. Total peak antibody titres ranged from 128-2048. Antibody to B lymphocyte antigens was identified in 8 of the 12 cattle. The responses to B lymphocyte antigens were similar to those against the more widely distributed common lymphocyte antigens with respect to time of antibody appearance, time of peak titre and sensitivity to 2-ME. Peak titres ranged from 2 to 32. The change in antibody specificity with time was also studied. Sera from 11 of the 18 cattle which had responded against lymphocytes showed an increase or broadening in reaction frequency as immunisations increased, suggesting the production of antibody to secondary specificities. In the cattle which had been skin grafted, the broadest reaction patterns were seen 14 to 21 days after grafting. The broadest reaction patterns were seen when the antibody responses were at their highest titre levels and narrowed as titres decreased.     

Coccidiosis: T-lymphocyte-dependent effects of infection with Eimeria nieschulzi in rats

The intestinal pathology caused by infection with $\text{Eimeria nieschulzi}$ was investigated and comparisons were made between the effects in athymic nude (rnu/rnu) rats and their heterozygous (rnu/+) litter-mates. Most of the changes noted, i.e. increase in gut weight, partial villous atrophy and increased numbers of mast, goblet and pyroninophilic cells were shown to be largely or wholely thymus dependent. The numbers of intraepithelial lymphocytes were decreased in both groups during the period of study. The peripheral blood leucocyte response was similar in both groups of rats during a primary infection but differed after a challenge inoculum, indicating that the secondary type of response which occurred in the rnu/+ rats was thymus dependent, as is resistance to reinfection.     

Serodiagnosis of Metastrongylus apri infection of pigs by immunofluorescence

The lyophilised first stage larvae of Metastrongylus apri were used as antigen in the indirect fluorescent antibody test for the diagnosis of the infection of pigs. The larvae were recovered from the embryonated eggs discharged by the gravid females of the nematode in vitro. Ten pigs were used in the test. Serial serum samples were taken of seven pigs, experimentally infected with varying doses of M. apri larvae, all of which were found to discharge eggs of the nematode in their faeces after infection was established. The other three pigs were uninfected and used as controls.Positive cuticular fluorescence of the larvae was first detected with the serum samples obtained between 14 and 33 days post-infection. This fluorescence persisted with subsequent serum samples up to 85 days post-infection. Pronounced and uniform cuticular fluorescence was generally observed with the serum dilutions of up to $\text{1}\text{10}$. Earlier post-infection serum samples either exhibited no cuticular fluorescence or gave non-brilliant fluorescence. The pre-infection serum of these pigs and also serum samples obtained from the three uninfected control pigs did not give cuticular fluorescence even at the initial serum dilution of $\text{1}\text{5}$.     

Serological responses of dogs to cell wall and internal antigens of Brucella canis (B. canis)

The serological responses of dogs to cell wall and internal antigens of B. canis were studied in experimentally infected specific-pathogen-free (SPF) Beagles. Sera from infected and false positive field dogs also were examined. Cell wall antigens were extracted from B. canis by two procedures that employed either hot phosphate buffered saline (PBS) or sodium desoxycholate (SDC). Agar gel immunodiffusion (AGID) tests employing sera from experimentally infected SPF dogs were used to evaluate antigenic extracts. Extraction with PBS yielded two antigens; SDC extracted an antigen complex and sonication of PBS extracted cells liberated four internal antigens.Sera from field dogs that were negative for B. canis infection in repeated tests often had heterospecific antibodies. Such cross-reactive sere commonly gave “spur” (partial fusion) reactions with a positive reference serum when tested against the SDC cell wall antigen. In addition, false positive dogs did not have antibody to one of the cell wall antigens or to the internal antigens. In contrast, sera from infected field dogs commonly gave “identity” (fusion) reactions in the AGID test with two antigens in the SDC extract, and produced precipitin lines to one to four internal antigens.Examination of a library of sera obtained from experimentally infected SPF dogs over a period spanning 4$\text{1}\text{2}$ years revealed that none of the serodiagnostic tests employed (tube agglutination, slide agglutination, AGID) was accurate during the inital 12 weeks of infection; hemocultures were the most sensitive during this period. Tube and slide agglutination tests were initially sensitive, but they showed a lack of sensitivity and specificity after the bacteremic period ceased, as well as in their failure to exclude false positive reactions in field animals. Immunodiffusion tests that employed SDC or PBS extracts of B. canis cell walls were sensitive and accurate in identifying most infected dogs. After the bacteremia had ceased, however, AGID tests that employed cell wall antigens gave equivocal results. Immunodiffusion tests that employed sonicated (internal) antigens were sensitive shortly after the onset of bacteremia, and they had the advantage of detecting infected animals for at least 6 months following the cessation of bacteremia, a time when other serological tests gave equivocal results.     

Humoral immune response of water buffalo monitored with three different antigens of Toxocara vitulorum

Humoral immune response of water buffalo naturally infected with Toxocara vitulorum was monitored using three different antigens of this parasite in serum and colostrum of buffalo cows and calves. Soluble extract (Ex) and excretory/secretory (ES) larval antigens and perienteric fluid antigen (Pe) of adult T. vitulorum were used to measure the antibody levels by an indirect ELISA. Serum of 7-12 buffalo cows for the first 365 days and colostrum of the same number of buffalo cows for the first 60 days of parturition, and serum of 8-10 buffalo calves for the first 365 days after birth were assayed. The ELISA detected antibodies against all three T. vitulorum antigens in the colostrum and serum of 100% of buffalo cows and calves examined. The highest antibody levels against Ex, ES and Pe antigens were detected in the buffalo cow sera during the perinatal period and were maintained at high levels through 300 days after parturition. On the other hand, colostrum antibody concentrations of all three antigens were highest on the first day post-parturition, but decreased sharply during the first 15 days. Concomitantly to the monitoring of immune response, the parasitic status of the calves was also evaluated. In calves, antibodies passively acquired were at the highest concentrations 24 h after birth and remained at high levels until 45 days coincidentally with the peak of T. vitulorum infection. The rejection of the worms by the calves occurred simultaneously with the decline of antibody levels, which reached their lowest levels between 76 and 150 days. Thereafter, probably because of the presence of adults/larvae stimulation, the calves acquired active immunity and the antibodies started to increase slightly in the serum and plateaued between the days 211 and 365. All three antigens were detected by the serum antibodies of buffalo calves; however, the concentration of anti-Pe antibody was higher than anti-EX and anti-ES, particularly after 90 days of age. By conclusion, the buffalo cows develop immunity and keep high levels of antibodies against T. vitulorum-Ex, ES and Pe antigens and these antibodies are transferred to their calves through the colostrum. This passively acquired immunity does not protect the calves against the acquisition of the infection, but these antibodies, passively or actively acquired, may have an important role during worm rejection by the calves and prevention of intestinal reinfection.     

Bovine babesiosis: The immunization of cattle with fractions of erythrocytes infected with Babesia bovis (syn B. argentina)

Soluble antigen which protected susceptible cattle against challenge with $\text{Babesia bovis}$ was extracted from $\text{B. bovis}$-infected erythrocytes by sonic disintegration and separation of the soluble from the insoluble matter by ultracentrifugation. The material was then fractionated by the precipitation of fibrinogen-like proteins. The precipitate contained the babesial antigens that were located on the stroma of the infected erythrocytes. Antigen originally located on the parasite remained in solution. Both fractions conferred protection on splenectomized calves against challenge with $\text{B. bovis}$. However, the fraction containing the parasite antigens appeared to have more potential for development as a killed vaccine because it was not heavily contaminated with antigenic material from bovine erythrocytes.     

Development of immune responsiveness to Ascarissuum antigens in pigs vaccinated with ultraviolet-attenuated eggs

Pigs fed $\text{Ascaris}$$\text{suum}$ eggs attenuated by short wave ultraviolet-radiation developed resistance to challenge infection. Per os inoculation of pigs on three successive weeks with 10,000 eggs irradiated to total exposures of 150,100 and 75 μW-min/cm², respectively, resulted in an 88% reduction in the number of larvae recovered from the lungs 7 days after challenge with 10,000 infective eggs. Peripheral blood lymphocytes (PBL) from vaccinated pigs were specifically stimulated in vitro to incorporate tritiated thymidine by egg hatching fluid (Ea) and by excretory-secretory products obtained from cultures in defined-media of second-stage larvae (L2) developing to third-stage (L2–3) and from cultures of third-stage larvae developing to fourth-stage (L3–4). PBL were also specifically stimulated by living L2. Ea and L2 stimulated pig PBL significantly at 7 days after the first inoculation; responses to L2–3 and L3–4 developed 7 days after a second inoculation. The antigen-responsive cells in the PBL population were non-immunoglobulin-bearing lymphocytes. Antibodies to Ea and L2–3 were not detected in the serum of vaccinated pigs, and only 3 of 7 pigs had low concentrations of serum antibodies to L3–4.     

A recombinant 31.5 kDa keratinase and a crude exo-antigen from Microsporum canis fail to protect against a homologous experimental infection in guinea pigs

A Microsporum canis recombinant 31.5 kDa keratinase and a M. canis crude exo-antigen were tested as vaccines in an experimental infection model in guinea pigs. Animals were vaccinated subcutaneously three times at two-week intervals with either the keratinase, the exo-antigen or the adjuvant alone. Cutaneous challenge was performed blindly. Both humoral and cellular-specific immune responses to M. canis antigens were evaluated every 14 days, while a blind evaluation of clinical lesion development and fungal persistency in skin were monitored weekly. Vaccination induced very high and significant (P < 0.01) antibody responses towards both antigens. High cell-mediated immune responses to both immunogens were also induced by vaccination. After challenge, however, scores reflecting the severity of dermatophytic lesions did not differ significantly between vaccinated and control groups at any time after challenge. These results suggest that, in the guinea pig, the induction of specific immune responses against the M. canis-secreted antigens used in this study are not protective against challenge exposure.     

Serum and abomasal antibody response of sheep to infections with Haemonchus contortus

Serum and abomasal IgA, IgG and IgM antibody response against adult worm, L3 and egg antigens of Haemonchus contortus was monitored by the ELISA technique after one or two infections with this nematode. Following the first infection, antibody levels in serum did not change materially. After administration of a challenge dose of infective larvae, antibodies of the three immunoglobulin classes in infected animals rose slightly, but this rise appeared later than the fall in the faecal egg counts. In contrast, in abomasal mucosa, IgA anti-larval antibody levels, which did not increase materially after the primary infection, rose rapidly after a transient inhibition when sheep were challenged. A close temporal relationship was observed between the rise in local anti-worm IgA antibodies and the self-cure reaction, but antibody levels fell rapidly after worm diminution. The local antibody response was thus considered to be related to immunity of sheep to H. contortus.     

Effects of ionizing radiation on in vitro proliferative responses of porcine peripheral blood lymphocytes

The radiosensitivity of $\text{in vitro}$ proliferative responses of porcine peripheral blood lymphocytes (PBL) was assessed. PBL were stimulated by Con-A, PHA, culture supernates from mitogen-stimulated porcine lymphocytes, or in the case of antigen-primed swine, specific antigens. The resulting levels of proliferation were assessed by a determination of the level of incorporation of tritiated thymidine $\text{in vitro}$, and in some cases by the presence of blast cells in the cultures. Porcine PBL were found to be more radioresistant than either mouse PBL or mouse spleen cells. Irradiation levels of greater than 3000 rads were necessary to arrest Con-A or PHA-induced proliferative responses. Proliferation induced by lymphokines in the form of supernates from mitogen-stimulated lymphocyte cultures was arrested in PBL that had received 3000 rads prior to culture. Antigen-induced proliferative responses in primed porcine PBL populations were the most radiosensitive, in that a previous irradiation with 500 rads was sufficient to completely abolish a secondary $\text{in vitro}$ proliferative response.     

Anti-enzyme antibodies in rabbits and pigs against Hyostrongylus rubidus (Hassall and Stiles, 1892)

Ether extracts of Hyostrongylus rubidus adult worms isolated on days 14, 35 and 64 of intection were found to contain two isoenzymes of malic dehydrogenase (MDH) and three of acid phosphatase. Sera from rabbits immunized against these extracts and sera from pigs experimentally infected with H. rubidus were tested for their anti-enzyme activity by two different techniques.Sera from rabbits actively immunized with a Day 14 worm extract contained an antibody which complexed only with a slow migrating isoenzyme of acid phosphatase but not with isoenzymes of MDH or acetylcholinesterase (AChE). No antibodies against worm acid phosphates or MDH were detectable by this technique in the sera of pigs which were experimentally infected with H. rubidus.A different technique, however, where the worm extracts were incubated at 60°C either with rabbit anti-H. rubidus serum, or serum from infected pigs, indicated the presence of anti-AChE globulin in both immunized rabbits and infected pigs. When individual immunoglobulins isolated from infected pigs were incubated with the same worm extract it was seen that activity was associated with IgG₁ but not with IgG₂, IgM or IgA. IgG₁ prepared from worm-free pigs did not complex with worm AchE. There was no interaction between the third stage larval AChE and pig IgG₁. Levels of AChE were highest in worms isolated at a period of infection when the hosts immune responses were beginning to manifest themselves and lowest in those worms surviving the population crisis.     

Brucella abortus antigen-induced lymphocyte reactivity in guinea pigs

A whole blood lymphyocyte transformation (WBLT) assay was used to detect anti-brucella lymphocyte reactivity in guinea pigs. Brucella antigens stimulated an antigen-specific lymphoproliferative response in WBLT assays from $\text{Brucella abortus}$ infected guinea pigs. The response was best detected from 6 to 16 weeks after challenge inoculation with viable $\text{B. abortus}$ 2308. Lymphocytes were not stimulated by unrelated bacterial antigens and control animals did not respond to the Brucella antigens. The responding cell population was characterized as mostly T lymphocytes. The WBLT assay was found to be specific for the detection of anti-brucella lymphocyte reactivity. However, a negative response was not definitive, which indicated a need for repeated testing to establish that a guinea pig did not have anti-brucella lymphocyte sensitization.     

Application of indomethacin as a potentiator of lymphocyte blastogenesis in Brucella abortus exposed cattle

Lymphocytes from $\text{Brucella abortus}$ field strain infected, strain 19 vaccinated, non-exposed and field strain infected, but immunologically unresponsive cattle were incubated with $\text{B. abortus}$ antigen and indomethacin. There were significant increases (P < 0.005) in the blastogenic responses, as measured by [³H] thymidine uptake, in cultures with indomethacin as compared to cultures without indomethacin. Lymphocyte blastogenic responses to $\text{B. abortus}$ antigen were potentiated by indomethacin in both $\text{B. abortus}$ exposed and non-exposed cultures. However, potentiation of sensitized lymphocyte blastogenic responses by indomethacin was significantly greater (P < 0.005) than that in non-exposed lymphocytes. Additionally, indomethacin significantly potentiated Brucella-induced lymphocyte blastogenic responses in lymphocytes from anergic cattle.     

The therapeutic efficacy and prophylactic activity of doramectin against Dictyocaulus viviparus in cattle

SUMMARY Three groups of 8, 4-month-old male Jersey or Jersey-cross calves were infected with 2400 Dictyocaulus viviparus L₃ larvae and either left untreated or injected subcutaneously with 200 μg/kg doramectin 5 or 25 days after infection (DAI). Lungworms were found in all untreated cattle (geometric mean = 49) at necropsy 39 or 40 DAI. None was found in any of the treated cattle. In a second experiment, groups of 6, 8-month-old calves were untreated or injected with 200 μg/kg doramectin 28, 21 or 14 days before each calf was challenged with 2700 D viviparus larvae. Lungworms were recovered at necropsy 32 to 34 DAI. The geometric mean worm burden in the untreated cattle was 550. This was reduced by 100%, 99.5% and 94.1% in calves treated with doramectin 14, 21 or 28 days, respectively, before infection. It was concluded that doramectin is a highly effective anthelmintic against D viviparus adult or L₄ infections of cattle, and that reinfection of treated cattle will be significantly reduced for at least 28 days after treatment.