Both CD8+ and CD16+ human T cell clones can provide B cell help for immunoglobulin production.
The functional properties of two CD4+CD8-CD16-, five CD4-CD8+CD16- and three CD4-CD8-CD16+ human T cell clones were compared. All CD4- T cell clones displayed strong cytolytic activity in the lectin-dependent lytic assay against the P815 murine mastocytoma cell line, but only the CD4-CD8-CD16+ T cell clones exhibited lytic activity against the natural killer-sensitive K562 cell line. Upon activation with anti-CD3 monoclonal antibody, all T cell clones were able to support IgM and IgA synthesis in autologous B cells. Both CD4+ and CD4- T cell clones required cell-to-cell interaction with the B cells in order to exert their helper activity for immunoglobulin production. However, unlike CD4+, CD4-CD8+CD16- and CD4-CD8-CD16+ T cell clones provided helper function for immunoglobulin synthesis only when low T/B cell ratios were used in culture. At higher T/B cell ratios, there was a decline in the B cell helper activity of CD4- T cell clones that was probably related to the expression of cytolytic capacity against the antigen-presenting B cell. These data support the notion that under certain experimental conditions even cytotoxic T lymphocytes and natural killer cells may provide B cell helper function.
Simonelli
C
C
Cattedra di Immunologia Clinica e Allergologia, Istituto di Clinica Medica, University of Florence, Italy.
Rugiu
F S
FS
Manetti
R
R
Parronchi
P
P
Piccinni
M P
MP
Almerigogna
F
F
Romagnani
S
S
Maggi
E
E
D000328:Adult; D015703:Antigens, CD / Q000276:immunology*; D000943:Antigens, Differentiation / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002999:Clone Cells / Q000276:immunology; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis*; D011961:Receptors, Fc / Q000276:immunology*; D017452:Receptors, IgG; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D015703:Antigens, CD; D000943:Antigens, Differentiation; D007136:Immunoglobulins; D011961:Receptors, Fc; D017452:Receptors, IgG