Delayed type Hypersensitivity reaction in bovine neosporosis

FIORANI F.; ARMENDANO J.; HECKER Y.P.; GUAL I.; LEUNDA M.R.; PEREYRA S.; ODEÓN A; MOORE D.P.

Athens

Simposio; 27th annual molecular parasitology & vector biology symposium; 2017

Center for tropical & emerging global diseases

Neosporosis is a parasitic disease caused by the protozoan Neospora caninum, wich is closely related to Toxoplasma gondii. N. caninum is a major concern in cattle industry and economic losses due to abortions have been estimated in over 1 million dollars worldwide. Little information is avilable regarding to a delayed type hipersensitivity (DTH) reaction in bovine neosporosis. In this study we examined the elicitation of a DTH reaction in cattle naturally and experimentally infected with N. caninum by intradermal inoculation with a soluble tachyzoite lysate at different concentrations: 0.5, 1 y 2 mg/mL and mock inoculums. Four experimental groups of 5 cows each one were as follow: seronegative (SN), seropostive (SP), inoculated with live tachyzoites of N. caninum (LNc) and inoculated with soluble tachyzoite lysate plus adjuvant (Sol-Adj). The intradermal reactions were measured at 0,24,48,72 and 96 hours post inoculation (hpi) in all groups. Development of specific antibodies were assesed by in house indirect ELISA. The intradermal reaction was statistically analyzed considering groups, inoculums and time as the main explicative variables. Noteworthy, observed and recorded between 24 and 96 hpi, but maximum increases were observed at 48 and 72 hpi in animals from groups SP and LNc. Interestingly, no development of specific antibodies were observed in any cows from SN group wicj is higly desirable since the only way to identify infected cattle is by performing serological tests. These results indicate that cows either naturally or experimentally exposed to N. caninum produced a DTH reaction, wich is a good indicator of the development of type 1 immune responses, wich is frequently associated to protection.