Both immunity and hyperresponsiveness to Pneumocystis carinii result from transfer of CD4+ but not CD8+ T cells into severe combined immunodeficiency mice.

AUTOR(ES)

Roths, J B

RESUMO

The opportunistic pathogen Pneumocystis carinii (Pc) is considered to be the leading cause of morbidity in patients with AIDS. It is important, therefore, to determine the immunological mechanisms of resistance to Pc. We have taken advantage of the lack of both T and B lymphocytes in severe combined immunodeficiency (scid) mice to determine the critical factors in resistance to spontaneously acquired Pc pneumonia. Using adoptive transfer of unfractionated or fractionated lymphocyte subsets or hyperimmune serum from congenic normal donors, we have demonstrated that effective immunity to Pc results from the action of CD4+ but not CD8+ T cells (in the absence of antibody) or from humoral immunity (in the absence of T cells). However, responses of CD4+ T cells (but not antibody) to already well-established burdens of Pc are often accompanied by a fatal hyperinflammatory reaction. The activity of CD4+ T cells against Pc thus illustrates a broadly applicable principle that T cell immunity represents a critical balance between consequences beneficial and harmful to the host.

Documentos Relacionados

• Immunity to Murine Chlamydia trachomatis Genital Tract Reinfection Involves B Cells and CD4+ T Cells but Not CD8+ T Cells
• Protective cellular retroviral immunity requires both CD4+ and CD8+ immune T cells.
• Feline immunodeficiency virus infects both CD4+ and CD8+ T lymphocytes.
• CD4+ and CD8+ T lymphocytes both contribute to acquired immunity to blood-stage Plasmodium chabaudi AS.
• Transfer of allergic airway responses with antigen-primed CD4+ but not CD8+ T cells in brown Norway rats.