A distinct population of nonphagocytic and low level CD4+ null lymphocytes produce IFN-alpha after stimulation by herpes simplex virus-infected cells.
Human PBMC were stimulated for 6 h in vitro by HSV or Sendai virus (SV) and analyzed by flow cytometry. IFN-alpha producing cells (IPC) were identified through their content of IFN-alpha mRNA by in situ hybridization using a 35S-labeled IFN-alpha 2 cRNA probe. The IPC induced by HSV-infected WISH cells lacked capacity to adhere to and phagocytose latex particles. The induction of IFN-alpha by free infectious SV occurring in monocytes was abolished by phagocytosis of latex particles present in the cultures during the induction period. Such latex particles actually enhanced the IFN-alpha response induced by glutaraldehyde-fixed HSV- or SV-infected WISH cells or by free intact HSV. The HSV-induced IPC did not express the CD14 Ag expressed on monocytes. Cell sorting was performed on HSV-induced PBMC labeled with phycoerythrin-conjugated anti-CD3 and FITC-conjugated anti-CD4 mAb. A small population consisting of 1.4% of all PBMC, which was CD3- but expressed low but significant levels of CD4, contained the majority of the IPC with a 50-fold increase of their frequency. This cell population had a forward- and right-angle light scatter different from typical monocytes/macrophages. The results therefore further delineate IPC among PBMC into monocytes, being stimulated by viruses such as SV. Another distinct population of infrequent but highly efficient IPC, tentatively designated natural IFN-alpha producing cells, is activated by stimuli such as HSV.
Department of Veterinary Microbiology, Swedish University of Agricultural Sciences, Uppsala.
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K
Sandberg
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P
Matsson
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GV
Alm
D000911:Antibodies, Monoclonal / Q000276:immunology; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D017252:CD3 Complex; D015704:CD4 Antigens / Q000032:analysis* / Q000276:immunology; D006561:Herpes Simplex / Q000378:metabolism*; D006801:Humans; D007370:Interferon Type I / Q000096:biosynthesis*; D008027:Light; D018950:Lipopolysaccharide Receptors; D008215:Lymphocytes, Null / Q000276:immunology*; D010587:Phagocytosis; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D012542:Scattering, Radiation
D000911:Antibodies, Monoclonal; D015214:Antigens, Differentiation, Myelomonocytic; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015704:CD4 Antigens; D007370:Interferon Type I; D018950:Lipopolysaccharide Receptors; D011948:Receptors, Antigen, T-Cell