Expansion of a lymphocyte population co-expressing T4 (CD4) and T8 (CD8) antigens in the peripheral blood of a normal adult male.
Approximately 2% to 3% of circulating human T cells co-express CD4 and CD8 (CD4+, CD8+) T-cell antigens. These CD4+, CD8+ cells may be immature precursors that function to replenish functional T-cell subsets. We detected a very high level of CD4+, CD8+ cells in the peripheral blood lymphocytes of a healthy white male, ranging from 21% to 36%. The morphology of his peripheral blood lymphocytes was normal, and he has maintained an elevated level of CD4+, CD8+ cells without clinical disease over a 19-month observation period. The CD4+, CD8+ cells did not possess thymocyte membrane antigen (CD6), nor did they have increased Tac (CD25) antigen. His intact, purified blood T cells had a normal proliferative response to phytohemagglutinin and interleukin-2 (IL-2), provided help for B-cell proliferation at control levels and exposure to IL-2 resulted in generation of cytotoxic cells. However, the purified blood CD4+, CD8+ cells were deficient in these latter functions except for help in B-cell function. Despite defective function, the isolated CD4+, CD8+ cells co-expressed CD2 and CD3. Prolonged in vitro culture of CD4+, CD8+ cells was possible in the presence of recombinant IL-2. The cultured CD4+, CD8+ cells retained the double antigens (CD4 and CD8) throughout a 4-week period. It is likely these cells are less mature than CD4+, CD8- or CD4-, CD8+ T cells as the CD4+, CD8+ have less in vitro function than the former cells, but it is not yet clear if they mature into either CD4+, CD8-, or CD4-, CD8+ cells. Finally, the presence of an expanded, hypofunctioning CD4+, CD8+ cell population in a normal adult male is apparently compatible with excellent clinical health.
Kay
N E
NE
Department of Medicine, Veterans Administration Medical Center, Minneapolis, MN 55417.
Bone
N
N
Hupke
M
M
Dalmasso
A P
AP
D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001773:Blood Cells / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology*; D016827:CD8 Antigens; D002478:Cells, Cultured; D006801:Humans; D008214:Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000502:physiology; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology / Q000648:ultrastructure; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D015704:CD4 Antigens; D016827:CD8 Antigens