Biomedical subjects

J Viac

Publications and source records attributed to J Viac.

147 records · Page 9Linked to original sources

PubMedDate not supplied

[Antigenic relations between human papilloma viruses (HPV): experimental study in guinea-pigs (author's transl].

A study of specific immune response in guinea-pigs after immunization with human papilloma viruses (HPV) purified from plantar warts, hand warts and condyloma acuminata is reported. The respective viruses induced the production of high antibody titres as well as specific cellular immunity as demonstrated by intradermal tests in all the animals. Formalin-inactivated HPV gave similar results. The antigenic cross reactions between the different viruses were evaluated by immunofluorescence and immunodiffusion tests and delayed hypersentitivity reactions. Serologically the results showed viral heterogeneity between condylomata and hand warts, and partial heterogeneity between condylomata plantar warts, and between hand and plantar warts. In skin-hypersensitivity reactions, however, the different viruses appeared as homologous antigens. This experimental study in guinea-pigs showed marked variance of specificity between delayed hypersensitivity reactions and humoral immunity for HPV.

Animals↗

PubMedDate not supplied

Papilloma viruses, warts, carcinoma and Langerhans cells.

In human papillomavirus (HPV) infections, Langerhans cells (LC) are essential in the control of viral infection. The evolution of HPV-derived lesions in the normal population and in graft patients is drastically different, since a high proportion of papillomas progress towards malignancy in transplant recipients. We analyzed the distribution of markers of LC and T lymphocytes, the level of keratinocyte activation and the prevalence of HPV in a series of epithelial lesions obtained from the normal population and from graft patients. The local immune response of warts, condyloma acuminata, Bowen, basal and squamous cell carcinomas (SCC) showed a moderate to intense inflammatory reaction of HLA-DR positive cells, the intensity of the immune reaction being correlated with the degree of malignancy. In the normal population, CD4-positive cells were mainly overexpressed in the dermal infiltrate of condyloma and malignant lesions, whereas in grafted patients such infiltrates were CD4- and CD8-positive without significant predominance of a single T cell subset. The epidermis of most lesions was characterized by a reduced number of CD1a-positive LC with an altered morphology. This was concomitant with the decrease or loss of beta 2-microglobulin by epithelial cells. HLA-DR antigen was sometimes expressed by keratinocytes in genital lesions and SCC from the normal population but has not been detected in immunosuppressed patients. Whereas in the normal population HPV infection was only detected in benign papillomas, both benign and oncogenic HPV DNA may be present in carcinomas from graft patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

CD40 expression in epidermal tumors.

CD40 antigen, expressed on many cell types is involved in cell-cell interactions, with activated T cells expressing the CD40 ligand. In the skin, keratinocytes express CD40 which may play a role in amplifying inflammatory responses. We investigated the expression of this antigen in a series of epidermal tumors in correlation with T cell infiltrates. Our results indicate a-down-regulation or a drastic loss of CD40 antigen by tumor cells from basal cell carcinoma and squamous cell carcinoma and a moderate to discrete CD40 reactivity of keratinocyte from proliferative layers of benign viral-induced lesions. Endothelial cells, most infiltrating cells and a subpopulation of intraepidermal dendritic cells strongly expressed CD40, mainly in benign lesions, in which T cell-keratinocyte interactions may be observed, and were restricted to epithelial cells expressing CD40. The lack of CD40 expression by tumor cells might account for tumor escape mechanism from activated T cells expressing the CD40 ligand.

Antigens, Neoplasm↗