[Detection of early humoral response in experimental toxoplasmosis in mice].

Experimental infection of mice by Toxoplasma gondii is the best way for antigen production or direct diagnosis. Early serological response from sera and peritoneal exudate of mice infected by T. gondii has been studied. In this report the authors show that specific antibodies (IgM) are found in the serum at 24 hours after intraperitoneal inoculation. Serological methods were unable to detect free antibodies in the peritoneal exudate. Specific antibodies coating the parasite surface were detected by direct immunofluorescence as soon as 48 hours post infection. Biochemical treatment usually used for antigen production (trypsin, pepsin) were unable to destroy this antibodies which where no longer detected after 2 mercapto-ethanol treatment. Control experiments showed that, in these conditions, 2 mercapto-ethanol treatment had no effect on the reactivity of surface antigens with antibodies. Therefore, this results show that checking for specific antibodies absorbed at the surface of T. gondii is a prerequisite of the use of antigen produced in vivo.