Cryopreservation of sheep red blood cells. 3. Complement titrations with frozen sensitized cells

The effect of different suspending and washing procedures for recovery of sensitized sheep erythrocytes (EA) after freezing at −196°C was investigated. Best results were obtained using gelatin-veronal-buffered saline-sucrose containing 0.15 mM-Ca and 1 mM-Mg (GVBSM⁺⁺-sucrose) as the suspending and first washing buffer. The cryoprotective agents tested were polyvinylpyrrolidone (PVP), neutralized PVP, purified PVP and a gum product, Avelex 1030. All PVP preparations tested gave good results as cryoprotectants in terms of cell recovery after thawing whereas Avelex 1030 was less satisfactory. The EA cells frozen in the presence of untreated PVP showed, however, increased susceptibility to the hemolytic action of complement, whereas cells frozen with purified or neutralized PVP gave titers similar to that obtained with fresh cells. Good results were also obtained with Avelex 1030. Complement titrations with frozen EA cells were more reproducible than titrations with fresh cells.     

Cryopreservation of Sheep Red Blood Cells: 4. Titrations of The First Complement Component with Frozen Eac4 Cells

The cryoprotection of the sheep erythrocyte intermediate EAC4 cells, used as reagent in titration of the first complement component, Gl, was investigated. The cryoprotective agents tested were untreated polyvinylpyrrolidone (PVP), purified PVP, neutralized PVP and a hydroxyethylated potato starch of high viscosity, Avelex 1030, hydrolyzed for 40 min. Recovery of EAG4 cells after thawing was 80–90 %, with best results using untreated, purified or neutralized PVP. The EAG4 cells frozen in the presence of untreated PVP showed, however, increased susceptibility to the hemolytic action of Gl, whereas cells frozen with purified or neutralized PVP or with Avelex 1030 gave titers similar to that obtained with fresh cells. Gl titrations with frozen and thawed EAG4 cells gave more reproducible results than those obtained when titrations were performed with fresh separately prepared cells.     

Serologic response to Brucella abortus of cattle and guinea pigs experimentally inoculated with a Yersinia enterocolitica serotype from milk

Ten strains of Yersinia enterocolitica belonging to ten various serogroups isolated from raw milk were inoculated into groups of five guinea pigs and five calves. Y. enterocolitica serotype 0:16 was the only serotype tested that induced an antibody response to Brucella abortus in calves. No anti-Brucella response could be demonstrated serologically in guinea pigs. Activity of the anti-Y. enterocolitica 0:16 calf sera against B. abortus antigen was shown by the tube agglutination test, and by the complement fixation test. The early agglutinating antibody response was partly sensitive to reduction by 2-mercaptoethanol. This sensitivity decreased later in the response. This is the first report of anti-Brucella responses induced by a serotype of Y. enterocolitica other than 0:9; sera from a group of five calves inoculated with 0:9 were tested by the same serological techniques for comparison.     

Demonstration of Alternative and Classical Complement Pathway Activity in Colostrum from Buffalo (Bubalus bubalis)

Buffalo colostrum caused lysis of unsensitized red blood cells (RBC) from sheep, goats, rabbits and chickens. RBC from cattle and buffalo were resistant to lysis. That lysis was due to the presence of natural antibodies to these RBC was ruled out since there was no reduction in haemolytic titres even after adsorption with the respective RBC. The addition of EGTA to the diluent had no effect on the haemolytic activity. These findings indicate the presence of alternative complement pathway (ACP) activity in buffalo colostrum. The haemolytic activity of buffalo complement for unsensitized rabbit RBC was reduced to very low levels by heating at 50°C for 45 min. Treatment with zymosan also inhibited the haemolytic activity, while inulin had no effect. The maximum activity of ACP occurred in the presence of 4 mmol/L Mg²⁺ in the diluent. The range of ACP activities in colostrum from buffaloes varied from 4.06 to 8.48 CH₅₀ units/ml. Using a standard system for titrating the classical complement pathway and rabbit red blood cells sensitized with goat haemolysin, the range of complement activity in buffalo colostrum was 4.81–6.77 CH₅₀/ml.     

Comparative evaluation of kinetic nephelometry for antibody detection

The sensitivity of the nephelometry performed as kinetic and end-point measurement for the detection of serum antibodies was evaluated in an experimental system and compared with that of the complement fixation and single radial immunodiffusion tests. The corresponding antibody titres of the used anti-FCS antiserum with BSA antigen were estimated to be 2⁻⁷ in complement fixation, 2⁻⁶ in single radial immunodiffusion and 2⁻⁴ in kinetic (rate) nephelometry tests. From the described findings it was concluded that the kinetic nephelometry with its present technical instrumentation provided a rapid serological technique to establish quantitative Heidelberger curves under experimental conditions but did not meet the required sensitivity for the detection of naturally occurring antibodies in infected donors.     

Bovine adenoviruses—IV. Two mixed antigens for routine serodiagnosis by complement fixation reaction

The frequency of bovine adenovirus infections occurring in cattle has been grossly underestimated up to the present day. Primary isolation of serotypes belonging to bovine subgroup II is cumbersome. Hardly any laboratory has used all 8 officially-recognised bovine serotypes in seroneutralisation-tests, which should be done when this type-specific method is used for serodiagnosis. The complement fixation test, known as group-reactive from human adenovirus serology, has failed to disclose the true incidence of bovine infections, as until recently the importance of a novel additional group-reactive bovine adenovirus antigen had been undisclosed. Here we describe production, composition and performance of two mixed antigens for complement fixation reactions, which take into account recent findings by our team on peculiarities of bovine adenovirus antigens. Mixed antigen 1 contains bovine serotypes 1, 2 and 3 and detects group-specific antibodies of the classical mastadenoviruses. Mixed antigen 2 contains bovine serotypes 4, 5, 6, 7 and 8 and determines group-specific antibodies against the novel paramastadenoviruses. In addition, each antigen is capable of demonstrating complement-fixing type-specific antibodies in sera against the respective types included in each mixed antigen, with a net enhancing effect produced by mixing. Use of the 2 mixed antigens promptly shows whether bovine adenoviruses, presently recognised as well as unclassified, are involved in a given outbreak of respiratory or enteric disease of cattle. If needed, the responsible type may be determined in a second step of serological investigation.     

A Serological Investigation into Contagious Caprine Pleuropneumonia (CCPP) in Ethiopia

For a comparison of serological tests for CCPP, sera from 767 goats were examined. They were subjected to three tests: complement fixation test (CFT) with Mycoplasma capricolum subspecies capripneumoniae antigen; blocking ELISA (B-ELISA) with Mycoplasma capricolum subspecies capripneumoniae antigen; and CFT with Mycoplasma mycoides subspecies mycoides small colony type antigen. Antibodies were detected by these three tests in 23%, 2% and 12%, respectively, of sera from districts in which CCPP had not been reported, and in 60%, 83% and 87%, respectively, in sera from areas in which CCPP had been reported. The specificity of the tests is discussed. The use of the B-ELISA test for the diagnosis and for epidemiological studies of CCPP is strongly recommended.     

Haemolytic Complement Activity and Humoral Immune Responses to Sheep Red Blood Cells in Indigenous Chickens and in Eight German Dahlem Red Chicken Lines with Different Combinations of Major Genes (dwarf,naked neck and frizzled) of Tropical Interest

A total of 376 chickens from different ecotypes were immunized with the non-pathogenic multi-determinant antigen sheep red blood cells (SRBC). The ecotypes included indigenous chickens from various locations in Tanzania (n=102), India (n=86) and Bolivia (n=89). In addition, eight German Dahlem Red (GDR) chicken lines with different major genes (dwarf, naked neck and frizzled) of tropical interest were also immunized with SRBC. Immune competence of the breeds was assessed by measuring complement haemolytic activity, both from the classical calcium-dependent complement pathway (CPW) and alternative calcium-independent complement pathway (APW), alongside IgTotal, IgG and IgM antibody responses to SRBC at 7 days post immunization. Large variations in complement activity and antibody responses to SRBC were observed within and between the indigenous breeds. Many indigenous chickens, especially from Bolivia, showed decreased complement activity (APW) following immunization with SRBC. Breeds from India showed the highest CPW activity and humoral (especially IgM) responses to SRBC, suggesting high immune competence. In contrast, Bolivian chickens were characterized by low CPW activity, low APW activity and low antibody levels to SRBC suggesting an overall low immune competence. In the GDR chickens, characterized by high CPW activity and high IgG antibody responses to SRBC, the major genes for naked neck, frizzling and dwarfism had no significant effect on the antibody responses and complement activity to SRBC.     

东亚夏季气候可预测性的一个论证

本文从冬季东亚西风急流与夏季副热带高压之间的动能互补与平衡关系出发,论证了夏季气候特征的可预测性在0.80以上,平均每10年(次)预测中可做到8年以上基本趋势正确。     

血尔宝补铁蛋白咀嚼片对大鼠胚胎致畸作用的研究

了解血尔宝补铁蛋白咀嚼片对SD大鼠胚胎的影响,将SD大鼠雌雄1:1交配,发现阴栓作为妊娠“零”天,检出的“孕鼠”随机分到阴性组、阳性组、高剂量组、中剂量组、低剂量组,并称重和编号。于妊娠第7～16d灌胃;受孕的0、7、12、16、20d称体重,并计算给受试物的量。孕鼠于妊娠20d处死,剖腹取子宫称重、取胎记录并检查胚胎、着床数、吸收胎、死胎和活胎数。活胎鼠记录胎仔体重、体长、尾长并检查胎鼠外观有无异常。半数活胎固定于鲍音氏液中固定两周后徒手切片作内脏检查,另半数活胎以茜素红作骨骼染色,并逐步检查骨骼。结果表示,20d孕鼠体重增长阳性组与阴性组、剂量组相比有显著差异(P<0.05);16d、20d孕鼠体重增长高剂量组与低剂量组相比有显著差异(P<0.05);各组相比着床总数无显著差异;活胎的仔数、吸收胎数、死胎数、平均仔重、体重、及尾长,阳性组与阴性组、剂量组相比有显著差异(P<0.05);阴性组、剂量组相比无显著差异(P>0.05);胚胎外形畸形率敌枯双阳性组为58.96%,与其它各组相比有显著差异(P<0.01)。阴性组和剂量组之间无显著差异(P>0.05)。表明血尔宝补铁蛋白咀嚼片对SD大鼠胚胎无致畸、毒性作用。