Immune reactivity to autochthonous ovine squamous cell carcinomata

The immune reactivity of tumor-bearing sheep to autochthonous tumor cells was investigated in the efferent lymph of a lymph node distant from the primary tumor site. This was done while the primary tumor was in situ and after its resection. The immune response to challenge with tumor cells while the primary tumor was in situ was associated with the detection of antibodies which were specific for the tumor cells but did not cause their demise. However, both humoral and cellular cytotoxic reactivities were detected in the lymph following removal of the primary tumor and rechallenge with tumor cells. This response had the characteristic of a secondary immune response which indicates sensitization to tumor antigens by the host. Thus the presence of the primary tumor has interfered with pre-existing host immunity.     

Successful isolation,cultivation and partial characterization of naturally occurring ovine squamous cell carcinomata

Seventeen epithelial cell lines have been successfully established from naturally occurring ovine squamous cell carcinomata. Culture establishment was most successful when tumor tissue was directly explanted rather than treated enzymatically. Success in establishing cultures also appeared to be related to the site on the body from which the tumor biopsy was taken, with tumors derived from the nose being most readily cultured. Several of the cell lines were successfully transplanted to nude mice where the growth patterns observed in the original host, i.e. expansive or invasive, were maintained. All cell lines assumed one of two distinct morphological types; however, no association could be seen between morphology and pattern of in vivo growth.     

Comparative histopathology of the lymph nodes, spleen, liver and kidney in experimental ovine trypanosomosis

The infection of Yankassa rams with three important trypanosome species affecting livestock, namely, Trypanosoma congolense, T. vivax and T. bruceiproduced both acute and chronic fatal conditions. Chronic infections were induced in the three infections by the application of subcurative doses of diaminazene aceturate (Berenil). Pathological changes in the infected animals included splenomegaly and hepatomegaly which were more pronounced in acute than in chronic T. congolense infection. However, these changes were more severe in chronic than in acute T. vivax infection. While splenomegaly was more pronounced in chronic T. bruceiinfection than in acute, hepatomegaly and lymphadenopathy were more severe in acute than in the chronic condition. The increases in size of the spleen, lymph nodes and liver were associated with congestion, increases in cell density related to increased immunological reactions in the spleen and lymph nodes as well as increase in numbers, size and activity of the phagocytic cells in these organs.     

Melanocytic cutaneous lesions and melanotic regional lymph nodes in slaughter swine.

During a five month period, 220 slaughter swine (at two abattoirs) had gross cutaneous and lymph node lesions suggestive of melanoma. Lymph nodes from 214 and cutaneous lesions from 176 of these pigs were submitted for histological examination. Of the cutaneous lesions, 174 were spontaneously regressing melanomas, and two were nonregressing. Regression usually commenced by infiltration of the lesion by lymphocytes, plasma cells and the formation of giant cells. Of the melanotic lymph nodes, 177 were diagnosed as melanosis, 35 were considered to be metastatic regressing melanomas, and two were nonregressing melanomas. This report indicates a high rate of spontaneous regression in swine melanomas detected at slaughter.     

Evidence of decreased concanavalin A induced suppressor cell activity in the peripheral blood and pulmonary lymph nodes of sheep with ovine progressive pneumonia

Concanavalin A (Con A) induced suppressor cell activity was evaluated in a group of ovine progressive pneumonia virus-antibody positive sheep (OPPV+). Decreased levels of suppressor activity were observed in the peripheral blood and regional pulmonary lymph nodes of animals with clinical and pathological evidence of ovine progressive pneumonia (OPP) when compared to animals with no lesions and animals with caseous lymphadenitis involving the lungs and pulmonary lymph nodes. Decreased levels of Con A stimulated lymphocyte proliferation was also observed in the peripheral blood and iliac lymph nodes of sheep with OPP. Sheep with OPP were found to be hypogammaglobulinemic. Sera from OPPV+ sheep had no effect on T and B cell mitogen stimulated responses of lymphocytes from sheep seronegative for antibodies to ovine progressive pneumonia virus (OPPV-) when compared to normal sheep serum.     

The sonographic evaluation of lymph nodes

Ultrasound can be used to detect and evaluate both normal and abnormal lymph nodes, as well as aid in biopsy sampling procedures, an important part of staging procedures in cancer patients. Several parameters can be evaluated using ultrasound; lymph node size, margins, echogenicity, echopattern (echotexture), acoustic transmission, presence and distribution of vascular flow, and vascular flow indices. The most diagnostically helpful include the short/long axis ratio of the lymph node, the pattern of distribution of the blood vessels within the lymph node, and to some extent the resistive and pulsatility indices. This review discusses the use of ultrasound for detecting, evaluating, and sampling peripheral, abdominal and thoracic lymph nodes in small animals.     

In vitro response of lymphocytes of normal and ovine squamous cell carcinoma-bearing sheep to phytomitogens and tumour extracts

A comparison was made of the blastogenic responses of peripheral lymphocytes (BRPL) of normal sheep with those of sheep bearing ovine squamous cell carcinoma (OSCC). In normal tumour-free sheep, BRPL to phytomitogens were found to vary in different age groups, and BRPL to OSCC extracts were found to become significantly elevated in sheep over one year old. In tumour-bearing mature sheep, BRPL to phytomitogens and to OSCC extracts decreased significantly with increasing maturity of tumours. The results are interpreted to show that increasing tumour volume, due to natural growth or enhancement, associates with increasing suppression of cell-mediated responses, and that such suppression may be a cause and a result of increased tumour volume.     

Antibody response of the ovine lymph node to experimental infection with an ovine abortion strain of Chlamydia psittaci

After primary infection with Chlamydia psittaci in the draining area of the popliteal lymph node, viable organisms could be isolated from the efferent lymph only before the primary immune response developed. The lymph antibody response, as assayed by the complement fixation and immunofluorescence (IF) antibody tests, showed a rise in titre that peaked approximately 2 weeks after infection. Immunoblotting revealed that antibodies produced during this period were predominantly directed against the major outer membrane protein (MOMP). In secondary infection of convalescent sheep, an elevated IF antibody titre, already present in the lymph and blood, could not be boosted. Viable organisms could not be isolated from these sheep. Antibodies produced reacted to 12-14 bands in the immunoblot profile including the MOMP band. These potentially immunoprotective antigens, particularly MOMP, should be considered as useful candidates for an improved vaccine against ovine enzootic abortion, in further investigations.     

Innate immune responses induced by classes of CpG oligodeoxynucleotides in ovine lymph node and blood mononuclear cells

CpG ODN signal through Toll-like receptor 9 (TLR9) and trigger a cascade of events that lead to activation of innate and adaptive immune responses. Our current understanding of the immunobiology of host responses to CpG is based largely on studies on peripheral blood mononuclear cells (PBMC) and splenocytes. Little is known regarding CpG-induced responses in other lymphoid tissues. In the present study, we investigated responses induced by CpG in both PBMC and lymph nodes. Cells were isolated from the superficial cervical lymph node (LNC) and blood and then stimulated with CpG ODN (either A-, or B- or C-class ODN). Cytokine production was assayed by ELISA, and lymphocyte proliferation was determined by (3)H-thymidine incorporation. NK-like cytotoxicity was analyzed by lysis of (51)Cr-labelled target cells. All three classes of CpG induced IFNalpha and IFNgamma in LNC. In contrast, only A and C-class ODN induced IFNalpha and IFNgamma in PBMC. Moreover, the IFN levels in LNC were 20-40-fold higher than in PBMC. Furthermore, all classes of ODN induced higher IL-12 levels in LNC (five- to six-fold) than in PBMC. Both B and C-class ODN induced good proliferative responses in PBMC and LNC, but the A-class ODN did not induce proliferation of PBMC and only induced moderate proliferation of LNC. A-class ODN induced significant NK-like activity in LNC. Thus, all three classes of CpG ODN induced similar responses in LNC, and these responses were consistently higher than in PBMC. These observations indicate that CpG ODN-induced responses differ between blood and lymph nodes, and suggest that the functional classification of CpG ODN based on PBMC responses may not be directly applicable to cells from other immune tissues.     

Feline Langerhans cells migrate from skin and vaginal mucosa to regional lymph nodes during experimental contact sensitization with fluorescein isothiocyanate

Recently, feline Langerhans cells (LC) were immunophenotypically characterized as CD1a+, CD4+, CD18+, CD53+ and MHC II+ cells. In mice, these cells are known to internalize antigens and to migrate to the lymph nodes (LN). In the cat, we have investigated the migration of LC from the skin and vaginal mucosa to regional LN in response to chemical exposure (fluorescein isothiocyanate). Three days after the administration of a FITC solution on the posterior limb of two male cats and in the vagina of one female, a biopsy was carried out on the draining LN of the sensitized zones. Immunostaining with monoclonal antibodies anti-CD79, anti-CD8, and antibodies recognizing LC was performed on cytospins and frozen sections of LN and showed that a majority of FITC+ cells displayed a LC immunophenotype and were localized in T-cell areas, but not in follicular areas. These results are the first evidence of migration of feline LC from skin and vaginal mucosa to the regional LN.     

Analysis of the humoral immune response to Oestrus ovis in ovine

Antibody responses (IgG, IgM and IgA) against Oestrus ovis were analyzed in sheep and in first year grazing lambs from Sardinia (Italy) by an indirect-enzyme-linked immunoassay test and L2 O. ovis excretory/secretory antigens. Serum samples from 208 sheep were obtained prior to be slaughtered, and then heads were removed and cut open along their longitudinal axis to collect the parasites from the nasal cavities, turbinates and sinus. Besides this, blood samples were monthly collected from the lambs of G-1 (maintained under field conditions) and the lambs of G-2 (kept housed since birth to avoid Oestrus infestations) throughout a year. In the sheep, a positive significant correlation was observed between the number of first instar O. ovis larvae and the values of IgM, and between the second instar larvae and the IgG optical densities. In the lambs, all classes of antibodies increased significantly from July in G-1. The highest values of IgG were reached in September (IgG) and decreased in November-December. The IgM response peaked in November, and very low values of IgA were observed during the study. Matching these data with chronobiology of O. ovis in this region, we conclude that the first infection occurs on May, stimulating the production of humoral antibodies. The reduction of the IgG antibody levels starting from October means the beginning of the diapause while the IgM response seems to be associated to the presence of L1 in the nasal cavities. The data obtained led us to forecast an early treatment of the ovine on June-July, which should keep away from the maturation of O. ovis L1 larvae, avoiding the development of clinical lesions and interrupting the life cycle of this parasite.     

Blood vessels of lymph nodes in the pig

Pig lymph nodes have an unusual arrangement of cortical and medullary tissue, and lack a hilus. The aim of the present study was to describe the pathways by which blood reaches these lymph nodes. Natural or synthetic latex casts were made of blood vessels of superficial inguinal, popliteal and jejunal lymph nodes. Major nodal arteries approach these lymph nodes and give rise to about five branches, most of which remain on the node surface. These branches often wrap around part or all of the node in a claw-like manner and they divide to form a network on its surface. Arteries from this network penetrate the capsule directly to supply the lymphoid parenchyma. Anastomoses are common at all levels between the arteries supplying the nodes and arteriovenous anastomoses occur within the nodes. These may help to maintain and regulate blood flow within the lymph node under different conditions of stimulation.     

The phagocytic cell response of the ovine lung to Pasteurella haemolytica

Conventionally-reared sheep were inoculated with (3.0 ± 0.6 × 10⁷) viable Pasteurella haemolytica type A1 by the intratracheal route and were killed immediately (0-time) or 2, 4, 12, 16, 24, 48 or 72 h later. Lung-wash cells and free bacteria were recovered by pulmonary layage.The number of recoverable bacteria tended to increase between 0-time and 4 h post-in-oculation (p.i.) then decline rapidly over the next 8 h. However, the rate of clearance was extremely variable and viable bacteria were recovered from $\text{3}\text{5}$ animals at 48 h p.i. and from $\text{1}\text{5}$ at 72 h p.i.In parallel with the clearance of the majority of the bacteria, total neutrophil numbers in the lung-wash rose to a peak of (36 ± 6) × 10⁸ cells/lung, which was, on average, 70-fold higher than 0-time levels. Their numbers remained constant from 12 to 24 h p.i. then fell to be 5-fold above 0-time levels at 72 h p.i. Macrophage numbers rose slowly throughout the experiment but most of the increase occurred between 24 and 48 h p.i. They reached a peak of (17 ± 11) × 10⁸ cells/lung at 48 h i.p. which was 3-fold higher than 0-time levels.