The primary humoral immune response of European green lizards (Lacerta viridis) to Leishmania agamae

Abstract

European green lizards, Lacerta viridis, produced relatively thermostable, dithiothreitol-sensitive, non-precipitating, agglutinins and complement-fixing antibodies (CFA) to Leishmania agamae administered subcutaneously (SC), intraperitoneally (IP) or orally (OR). Antibodies were also detected by the immobilization test (IMM) and by enzyme-linked immunosorbent assay (ELISA). The most sensitive method for the detection of stimulated immunoglobulins was ELISA. Antibodies were detected as early as 3 days post-infection with ELISA and between 5 and 7 for CFA, direct agglutination (DA) and indirect haemagglutination (IHA). In the case of IMM, the times of first detection varied from 14 to 28 days. Maximum CFA (2(-8)), DA (2(-8)), IHA (2(-11)) and ELISA (2(-16)) titres were reached from 42 to 49 days with significantly higher values occurring in the OR and IP groups. With IMM, maxima occurred after 5 or 6 weeks. Following exposure, two- to five-fold significant increases in serum lysozyme levels were demonstrated but the concentrations in sera following SC, IP or OR routes of antigen administration were not significantly different when the groups were compared with each other. The highest lysozyme values (approximately 12.3 - 12.5 micrograms ml(-1)) were found in the SC and OR groups when compared to the IP (7.40 micrograms ml(-1)).