EOSINOPHILIA, IGE PRODUCTION, AND CYTOKINE PRODUCTION BY LUNG T-CELLSIN SURFACE CD4-DEFICIENT MUTANT MICE INFECTED WITH TOXOCARA-CANIS

Mutant mice deficient in CD4(+) T cells and their normal and heterozyg ous littermates were infected with Toxocara canis, and compared for eo sinophilia, total and Toxocara-specific immunoglobulin E (IgE) product ion, and in vitro cytokine production by lung cells, The numbers of eo sinophils in the peripheral blood of normal and heterozygous mice peak ed on days 10 and 21, although mutant mice showed eosinophilia with a peak on day 10. This indicates that the first peak on day 10 is CD4 in dependent and the second peak is CD4 dependent. Before infection, the levels of total IgE had no significant difference among the three grou ps of mice. Total and Toxocara-specific IgE in all genotypes of mice i ncreased after infection, and was the highest in normal mice and the l owest in mutant mice. In vitro production of interleukin (IL)-5 and IL -4 by total lung cells was the highest in normal mice and the lowest i n mutant mice. CD4(+) and CD4(-) CD8(-) T lymphocytes, but not CD8(+) T lymphocytes produced IL-5 and IL-4 when incubated with anti-CD3 mono clonal antibody (mAb) and lung-adherent cells. These results indicated that IL-5 and IL-4 were produced mainly by CD4(+) cells and partly by CD4(-) CD8(-) cells, but not by CD8(+) cells. In addition, cytokine p roduction by CD4(+) cells was affected by the number of CD4 molecules on their surface.