TOXOCARA-CANIS ADULT WORM ANTIGEN INDUCES PROLIFERATIVE RESPONSE OF HEALTHY-HUMAN PERIPHERAL-BLOOD MONONUCLEAR-CELLS

The proliferative response of human peripheral blood mononuclear cells (PBMC) from healthy donors to Toxocara canis adult worm antigens (TcA ) was examined. PBMC from all donors examined (n = 7) strongly respond ed to TcA in a dose-dependent fashion after six days of culture, irres pective of their serological reactivity. In contrast, cord blood monon uclear cells did not react to TcA. The proliferation of PBMC in respon se to TcA was completely inhibited by anti-HLA-DR antibody. Purified C D4(+) T cells reconstituted with autologous irradiated antigen present ing cells (APC) vigorously proliferated in response to TcA, but this w as abrogated by pretreatment of APC with paraformaldehyde. Significant IL-2, IL-3, IL-4, IL-5 and IFN-gamma mRNA expression was detected in PBMC stimulated with TcA, with expression peaking at 72 h after stimul ation. IL-1 beta, IL-6, IL-10 and GM-CSF mRNA expression was also upre gulated, peaking at 24 h after stimulation. Taken together, these resu lts suggest that adult T. canis-derived antigens have the ability to a ctivate human PBMC as conventional antigens, possibly due to their cro ss-reactivity, which may be involved in the host defence against helmi nth infection.