DIFFERENCIAL INVESTMENT IN CELL IMMUNE RESPONSE ON RATS INFECTED WITH Trypanosoma cruzi AND/OR Trichinella spiralis EXPOSED TO FOOD RESTRICTION

PONTARELLI F; CUERVO P; RUIZ M; RACCA AL; PALAVECINO C; FANTOZZI C

Otro; IV Reunión Conjunta de Sociedades de Biología de la República Argentina; 2020

One of the most studied resistance mechanisms is the immune response. The variability of investment in such a mechanism has been shown to be modulated by the context faced by animals in the wild. The aim of this study is to evaluate the leucocyte profile as an indicator of the investment in cellular immunity in a model of infection by Trichinella spiralis and/or Trypanosoma cruzi in laboratory rats exposed to food restriction. Both parasites are etiological agents of zoonotic diseases of relevance in Argentina, and rodents can participate as reservoir and transmission sources. After four weeks of exposure to food restriction or no challenge (control), the rats were inoculated with one of the parasites or both. Two weeks after infection, the absolute differential counts were evaluated. Lymphocyte count raised in animals exposed to Try. cruzi alone and in co-infection, more markedly in food restriction; while in those infected with Tri. spiralis the count tended to decrease. The amount of eosinophils increased in food restricted animals in presence of mono-infection with Tri. spiralis, while in control animals the increase was less pronounced. Contrary to what we expected, no significant changes in neutrophil counts were observed. Finally, the monocyte count decreased in rats infected with Tri. spiralis and increased in the presence of Try. Cruzi in both treatments, although more markedly in food restriction. The increase of eosinophils in the presence of Tri. spiralis is expected in helminth infections. However, such trend was not maintained in co-infection. This would indicate a modulation of the response to nematodes in presence of another infection and a greater investment during scarcity of resources. The greater increase in monocytes and lymphocytes in food restriction compared to the control group in the presence of the protozoan could be demonstrating a modulation of the strategy in scarcity of resources. In the other hand, the decrease in the number of lymphocytes is expectable in the presence of Tri. spiralis. This results are relevant for the understanding of the variability of the investment in resistance and its consequences in the modulation of the defense strategy. Rodents play a key role in the transmission of innumerable diseases of economic and health importance, so understanding the determinants that modulate their capacity as reservoirs is essential in veterinary medicine and public health.