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.
Retrovirus Diseases Branch, Centers for Disease Control, Atlanta, Georgia 30333.
R B
RB
Lal
D L
DL
Rudolph
T
T
Rowe
T M
TM
Folks
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