Comparison of the significance of CD4+ and CD8+ T lymphocytes in the protection of mice against Encephalitozoon cuniculi infection.

The role of T lymphocyte subpopulations in the protection against intraperitoneal (i.p.) and peroral Encephalitozoon cuniculi infections was compared in adoptive-transfer experiments using severe combined immunodeficient mice. Whereas CD8+ T cell-depleted, but not CD4+ T cell-depleted, BALB/c splenocytes failed to protect the mice against i.p. infection, only SCID mice reconstituted with both CD4+ T lymphocyte- and CD8+ T lymphocyte-depleted splenocytes succumbed to peroral infection. The results indicate that whereas CD8+ T cells are critical for the protection against an i.p. E. cuniculi infection, both CD4+ and CD8+ T lymphocyte subpopulations play a substantive protective role in a peroral infection, i.e., natural route of infection.

Role of CD4+ and CD8+ T lymphocytes in the protection of mice against Encephalitozoon intestinalis infection.

Severe combined immunodeficient (SCID) mice reconstituted with spleen cells from naive adult BALB/c mice were completely resistant to peroral infection with Encephalitozoon intestinalis (Calli, Kotler and Orenstein, 1993) Canning, Field, Hing and Marriott, 1994, whereas control, non-reconstituted SCID mice succumbed to the infection. The role of T-lymphocyte subpopulations in the protection against peroral E. intestinalis infection was studied in adoptive transfer experiments using SCID mice. SCID mice reconstituted with both CD4+ and CD8+ T-lymphocyte-depleted splenocytes succumbed to the peroral route of infection. In contrast, SCID mice reconstituted with either CD4+-depleted or CD8+ T-lymphocyte-depleted splenocytes completely resolved the infection. This indicates that CD4+ and CD8+ T-lymphocyte subpopulations play a substantive role in protection against peroral infection with the microsporidian, E. intestinalis.