Phenotypic expression of integrin membrane receptors on spontaneously proliferating CD8 cells in human T-lymphotropic virus type II (HTLV-II)-infected individuals.
Spontaneous lymphocyte proliferation in the absence of exogenous stimulators was examined in asymptomatic HTLV-II-seropositive (n = 12) and seronegative individuals (n = 16). Mean spontaneous lymphocytic proliferation significantly increased on day 8 postculture in HTLV-II-infected individuals (5762 +/- 899 cpm) compared with normal controls (2034 +/- 925 cpm, P less than 0.01). The proliferating cells in infected individuals were predominantly T cells; neither B cells nor monocytes demonstrated any proliferation. Phenotypic analysis of cultured cells from individuals with HTLV-II infection demonstrated differential expression of integrin molecules as defined by anti-CD29 and anti-S6F1 (42.8 +/- 4.2 and 39.6 +/- 5.9%, respectively) on CD8 cells, as compared with day 0 peripheral blood mononuclear cells (PBMC) from infected individuals (19.7 +/- 3.5 and 19.9 +/- 1.9%, respectively) or normal controls (12.9 +/- 3.1 and 11.5 +/- 2.5%, respectively; P less than 0.001 for both comparisons). These CD8+ cells did not express CD16 or CD11b. The culture supernatants derived from the spontaneously proliferating cells had significantly increased levels of sCD8 and sCD25 (765 +/- 180 and 1805 +/- 320 U/ml, respectively) compared with those from normal controls (222 +/- 120 and 305 +/- 90 U/ml, respectively; P less than 0.01). Furthermore, culture supernatants derived from spontaneously proliferating PBMC from HTLV-II-infected individuals had no detectable levels of HTLV antigen and did not stimulate proliferation of PBMC from normal donors. These results suggest that the spontaneous proliferation in HTLV-II asymptomatic carriers is due to expansion of CD8 cells expressing integrin receptors which may serve as costimulatory molecules for their activation.
Lal
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Retrovirus Diseases Branch, Centers for Disease Control, Atlanta, Georgia 30333.
Rudolph
D L
DL
Rowe
T
T
Folks
T M
TM
D000328:Adult; D015703:Antigens, CD / Q000276:immunology; D018845:CD11 Antigens; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D015487:HTLV-II Antigens / Q000276:immunology; D015491:HTLV-II Infections / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D019012:Integrin beta1; D016023:Integrins / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012698:Serologic Tests; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D015703:Antigens, CD; D018845:CD11 Antigens; D015487:HTLV-II Antigens; D019012:Integrin beta1; D016023:Integrins; D016169:Lymphocyte Function-Associated Antigen-1