Spontaneous lymphocyte proliferation in HTLV-I/II infection reflects preferential activation of CD8 and CD16/56 cell subsets.
Previous studies have shown that lymphocytes from HTLV-infected persons spontaneously proliferate when cultured in vitro. We investigated which cell subsets become activated in this response. Mononuclear cells from 16 HTLV-seropositive former blood donors and 9 seronegative controls were cultured for 7 days; activation was then assessed by measuring DNA synthesis in cultured cells and by monitoring CD25 expression by CD3, CD4, CD8, CD19, and CD16/56 lymphocyte subsets. Of the 16 cultures of HTLV + donor cells, 10 showed spontaneous proliferation (Prol + group) and 6 did not (Prol - group). Cytofluorometric analysis revealed a significant increase in the fractions of CD8 cells and CD16/56 cells expressing CD25 for the Prol + group, compared to the Prol- and control groups. Similarly, the fractions of CD25 cells expressing CD8 or CD16/56 were significantly increased in the Prol + group. Although neither the fraction of CD4 cells expressing CD25 nor the fraction of CD25 cells expressing CD4 were increased for the Prol + group, the modal fluorescence intensity value for CD25 expression by CD4 cells was increased, suggesting some CD4 cell activation occurred as well. Blastoid cells were, on average, 79% CD25 +, whereas the sum of CD4 + CD25 + (27%), CD8 + CD25 + (30%), CD19 + CD25 + (3%), and CD16/56 + CD25 + (35%) subsets was 95%; the presence of 17% CD8 + CD16/56 + cells accounted for most of this discrepancy. These findings indicate that spontaneous lymphocyte proliferation in HTLV infection reflects preferential activation of CD8 and CD16/56 cell subsets, apparently including the minor CD8 + CD16/56 + subset.
Prince
H E
HE
Cellular Immunology Laboratory, American Red Cross Blood Services, Los Angeles, California 90006.
Weber
D M
DM
Jensen
E R
ER
D015703:Antigens, CD / Q000032:analysis / Q000096:biosynthesis*; D000943:Antigens, Differentiation / Q000096:biosynthesis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis; D019002:CD56 Antigen; D016827:CD8 Antigens; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D006800:Deltaretrovirus Infections / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation / Q000276:immunology*; D016131:Lymphocyte Subsets / Q000276:immunology*; D008214:Lymphocytes / Q000502:physiology*; D011961:Receptors, Fc / Q000096:biosynthesis; D017452:Receptors, IgG; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis
D015703:Antigens, CD; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D019002:CD56 Antigen; D016827:CD8 Antigens; D011961:Receptors, Fc; D017452:Receptors, IgG; D015375:Receptors, Interleukin-2