Fas-independent cytotoxicity mediated by human CD4+ CTL directed against herpes simplex virus-infected cells.
The present study was undertaken to clarify the mechanisms of cytotoxicity mediated by virus-specific human CD4+ CTLs using the lymphocytes of family members with a Fas gene mutation. CD4+ CTL bulk lines and clones directed against HSV-infected cells were established from lymphocytes of a patient with a homozygous Fas gene mutation and of the patient's mother. HSV-specific CD4+ CTLs generated from lymphocytes of the patient and her mother exerted cytotoxicity against HSV-infected cells from the patient (Fas-/-) and from her mother (Fas+/-) to almost the same degree in an HLA class II-restricted manner. mRNAs for the major mediators of CTL cytotoxicity, Fas ligand, perforin, and granzyme B, were detected in these CD4+ CTLs using the RT-PCR and flow cytometry. The cytotoxicity of the HSV-specific CD4+ CTLs appeared to be Ca2+-dependent and was almost completely inhibited by concanamycin A, a potent inhibitor of the perforin-based cytotoxic pathway. Although the Fas/Fas ligand system has been reported to be the most important mechanism for CD4+ CTL-mediated cytotoxicity in the murine system, the present findings strongly suggest that granule exocytosis, not the Fas/Fas ligand system, is the main pathway for the cytotoxicity mediated by HSV-specific human CD4+ CTLs.
Yasukawa
M
M
First Department of Internal Medicine and Department of Pediatrics, Ehime University School of Medicine, Shigenobu, Ehime, Japan. yasukawa@m.chime-u.ac.jp
Ohminami
H
H
Yakushijin
Y
Y
Arai
J
J
Hasegawa
A
A
Ishida
Y
Y
Fujita
S
S
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000494:pharmacology; D002999:Clone Cells; D003241:Consanguinity; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D053938:DNA Fragmentation; D053222:Fas Ligand Protein; D005260:Female; D053804:Granzymes; D006561:Herpes Simplex / Q000276:immunology*; D006579:Heterozygote; D006650:Histocompatibility Testing; D006720:Homozygote; D006801:Humans; D018942:Macrolides; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D010375:Pedigree; D054353:Perforin; D017354:Point Mutation; D052899:Pore Forming Cytotoxic Proteins; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000235:genetics; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D019014:fas Receptor / Q000235:genetics* / Q000276:immunology
D000900:Anti-Bacterial Agents; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D018942:Macrolides; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D019014:fas Receptor; D054353:Perforin; C036978:concanamycin A; C509213:GZMB protein, human; D053804:Granzymes; D012697:Serine Endopeptidases; D002118:Calcium