The effect of transfer factor on lymph node morphology in murine toxoplasmosis

Mice were infected intraperitoneally with a low virulence strain of Toxoplasma gondii (TO) and transfer factor (TF) was prepared from the spleens of infected (TFT) and uninfected control mice (TFC). Three experimental groups of 12 mice were given either saline, TFC or TFT, by intraperitoneal injection. After 24 h half of each group of these animals were infected by intraperitoneal injection of TO cysts. In three separate experiments animals were killed at 11, 28 and 35 days and the flank and axillary nodes removed for histological examination. There was generalized lymph node enlargement with cortical and paracortical expansion. In most animals there was diffuse infiltration of the nodes by clusters of histiocytes. Administration of TFC alone led to a mild increase in node size at 11 and 28 days. Administration of TFT alone had a moderate stimulatory effect on the mouse lymph nodes with a significant increase in size at 11 days due predominantly to expansion of the paracortex. Administration of TFT and TFC followed by inoculation of TO led to an increased and more consistent histiocyte response and an increased number of paracortical T blasts compared with animals given TO alone. TFT and TFC had no demonstrable protective effect in experimental murine toxoplasmosis as assessed by quantitation of toxoplasma brain cysts. The effect of transfer factor was not antigen specific in this system.