[Immunity of the female genital tract mucosa and mechanisms of papillomavirus evasion].
Human papillomaviruses (HPV) are responsible for many cutaneous and mucosal lesions. Some viral genotypes are considered to be the causal agents of cervical cancer. Natural genital HPV infection seems to be poorly immunogenic because of its nonproductive and noninflammatory characteristics and also because of the different mechanisms developed by the virus to counteract the immune response. Knowledge of the immune system organization and its regulation in the human female genital tract needs to be clarified. It is mostly "programmed" to ensure a humoral response. Nevertheless, secretory IgA, that are particularly efficient for anti-infectious mucosal immunity are poorly present in physiological vaginal secretions. These distinctive features could explain part of the relative immune deficiency against HPV. Moreover, reduction or loss of MCH1 molecules and a defect in antigen presentation to cytotoxic lymphocytes could in part explain the cytotoxicity deficiency. There is however clear evidence that cellular immune response plays a major role in the control and course of HPV infection. This response varies according to the grade of the lesion and to the oncogenic potential of the infecting HPV. A deficiency in induction of cellular cytotoxicity mechanisms seems to be involved in the persistence of HPV infection and so in carcinogenesis. Finally, worldwide cervical cancer incidence (5000000 new cases per year) warrants effective vaccine developments. Two strategies, one preventive and one therapeutic, are now under study. Vaccine adjustments are based first on humoral immunity induction with production of neutralizing antibodies for prophylaxis and second on cellular immunity induction to kill cells with viral oncoprotein expression for therapy.
Riethmuller
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Service de Gynécologie-Obstétrique, CHU Besançon, et EA 2085, Faculté de Médecine et de Pharmacie, 25000 Besançon.
Seilles
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D000917:Antibody Formation; D002584:Cervix Uteri / Q000276:immunology; D005260:Female; D005836:Genitalia, Female / Q000276:immunology*; D006801:Humans; D007109:Immunity; D007111:Immunity, Cellular; D009092:Mucous Membrane / Q000276:immunology*; D027383:Papillomaviridae / Q000276:immunology*; D030361:Papillomavirus Infections / Q000276:immunology*; D014412:Tumor Virus Infections / Q000276:immunology*; D002577:Uterine Cervical Diseases / Q000821:virology