Hemolytic assay for goat (caprine) and swine (porcine) complement

The complement system of the goat: haemolytic assays and isolation of major proteins

BACKGROUND

The aim of the present study was to develop a haemolytic assay for the study of the complement system in dairy goats (Capra aegagrus hircus) and to characterize the major goat complement system proteins.

RESULTS

The commonly used sheep erythrocyte sensitized with rabbit antibodies were not sensitive to lysis by goat serum, but the combination of human red blood cells (RBC) plus rabbit antibodies was the best option found for goat complement assay. A buffer based on HEPES instead of the classical veronal (barbitone) was developed. Three proteins were isolated: factor H, C1q and C3 and these were compared with the corresponding human proteins. A novel affinity chromatography technique was developed for isolation of factor H.

CONCLUSIONS

Human RBC plus rabbit antibodies were a suitable option for haemolytic assays. The isolated proteins are similar to the human counterparts.

Studies on the haemolytic complement of the dromedary camel (Camelus dromedarius). I. Classical pathway haemolytic activity in serum

Classical pathway haemolytic complement (CPHC) of the dromedary was assayed under standardised conditions. A total of 14 indicator systems of red blood cells (RBC) and haemolysins were investigated. Highest CH50 titre was obtained with rabbit RBC sensitised with goat haemolysin. Among the factors investigated were: ionic strength, Mg2+, Ca2+, ethylenediaminetetraacetic acid (EDTA) concentration, pH, incubation time and temperature. The standard system of titrating the HC levels consisted of rabbit RBC sensitised with goat haemolysin, sucrose veronal buffer (SVBS) pH 7.4, ionic strength 0.14 M and Ca2+ and Mg2+ concentrations of 4.0 x 10(-4) M and 1 x 10(-3) M, respectively. Incubation at 37 degrees C for 120 min gave the highest HC activity. Using these standardised conditions HC levels were determined in 79 camels aged between 3 months and 15 years. Highest mean HC value of 873 +/- 26.6 CH50 units ml-1 were recorded in the age group of 1-5 year old camels and the lowest mean HC value of 598 +/- 120.8 CH50 units ml-1 in the age group of 10-15 year old camels. Adult males in the age group 5-10 years had significantly higher mean HC levels than their female counterparts (P < 0.0001).

Determination of optimal in vitro conditions for caprine alternative complement pathway assay

Optimal in vitro testing conditions for caprine alternative complement pathway assay were determined. Effects of the following variables were tested: heterologous erythrocytes; pH, ionic strength and Mg2+ ion concentration of the complement diluent; incubation time and temperature. Rabbit erythrocytes were the optimal target cells. The optimal buffer conditions were: pH 8.0, ionic strength 0.06 mmol NaCl and 5mmol Mg2+ ion. Optimal incubation time and temperature were 75 min and 30 degrees C, respectively.

Studies on activation and levels of haemolytic complement of buffalo (Bubalus bubalis). 1. Classical complement pathway

Optimum conditions for haemolytic complement (HC) assay in buffalo serum were standardized. In all, 11 indicator systems of red blood cells (RBC) and haemolysins were investigated. Maximum HC CH50 titre was obtained with rabbit RBC sensitized with goat haemolysin. The effect of pH, Ca2+ and Mg2+ concentration, ionic strength, time and temperature were studied. Of all the variables, ionic strength influenced the HC activity most significantly. The standard system for titrating the HC consisted of rabbit RBC sensitized with goat haemolysin, sucrose-veronal buffer with pH 7.5, ionic strength 0.023 M and Ca2+ and Mg2+ concentrations 6 x 10(-4) and 2 x 10(-3) M, respectively. Incubation at 37 degrees C for 2 h gave highest haemolytic activity. With this protocol 5-7-fold higher HC activity was recorded than with prestandardized conditions. Levels of HC were determined in the sera of 98 buffaloes aged from 1 month to 12 years. The lowest mean CH50 units of 401 +/- 0.35 per ml were recorded in buffalo calves below 3 months of age. The mean HC levels increased with age, reaching peak values of 2349 +/- 62.25 CH50 units/ml in 2-3-year-old buffalo. Animals in the age group 5-12 years had significantly decreased (P less than 0.05) mean HC levels of 1545 +/- 68.94.

Laboratory techniques of veterinary clinical immunology: a review

Laboratory tests currently used or easily applicable in veterinary clinical immunology were reviewed in the following three categories: (1) tests detecting disorders in humoral immune response: serum protein screening tests, gammaglobulin estimation and complement testing; (2) tests detecting disorders in cellular immune response: phagocyte function tests and lymphocyte function tests; (3) tests detecting autoimmune disorders: detection of antinuclear antibodies, rheumatoid factor, autoimmune hemolytic diseases, and autoimmune organ and tissue disorders. The principles of the tests and the interpretations of the results are presented with the appropriate references.