Langerhans cells of the ocular surface.

Dendritic cells (DC) in 121 colorectal adenocarcinomas were investigated immunohistochemically, using anti-S-100 protein antibody. S-100(+)DC were recognized among the malignant cells and/or around the tumor and differed in distribution either from lysozyme-positive macrophages or from neuron-specific enolase-positive neural tissue. Patients with many S-100(+)DC (more than 30 cells per 10 high-power fields) in the tumor survived longer than did those with few such cells (less than 30 cells), most often with no metastases (P less than 0.001). The grade of S-100(+)DC infiltration was related to both density of lymphocytic infiltration in the primary tumor and the degree of paracortical hyperplasia in the regional lymph nodes (P less than 0.05). Dendritic cells, therefore, as antigen-presenting cells, conceivably mediate cell immunity in a tumor with lymphoid infiltration and in the regional lymph nodes. The number of S-100(+) DC in the primary colorectal carcinomas represents one aspect of such a series of antitumor immunoreaction, in vivo.

https://acsjournals.onlinelibrary.wiley.com/doi/pdf/10.1002/1097-0142%2819890201%2963%3A3%3C496%3A%3AAID-CNCR2820630318%3E3.0.CO%3B2-K

S‐100 protein‐positive dendritic cells in colorectal adenocarcinomas. Distribution and relation to the clinical prognosis

S100 positive dendritic cells in human lung tumors associated with cell differentiation and enhanced survival

The presence of Langerhans ceils (LCs) in the epidermis was first observed in 1868 by Paul Langerhans after he had stained sections of skin with gold chloride (Langerhans 1868). Although LCs cannot be seen in routine histologic sections of skin by light microscopy, they can easily be identified with the use of special stains; however, these stains may not always be specific, especially in identifying LCs in sites other than the epidermis. It was not until 1961, when the ultrastructural features of LCs were described, that progress was made in defining LCs (Birbeck et al. 1961). By electron-microscopic examination they are dendritic cells, which can be distinguished by a relatively clear cytoplasm, a lobulated nucleus, and unique organelle.s the Langerhans cell granules. These cells lack desmosomes, tonofilaments, melanosomes and premelanosomes which are characteristic for keratinocytes or melanocytes.

Langerhans Cells: Role in Contact Hypersensitivity and Relationship to Lymphoid Dendritic Cells and to Macrophages

To understand the biologic processes involved in transmission of HIV, we examined the genital tracts of chronically infected female macaques and localized SIV-infected cells. SIV was found in the genital tract of 12 of 16 animals and SIV-infected cells were located in the cervix and vagina. Inoculation of cell-free SIV into the blind vaginal pouch of hysterectomized macaques resulted in systemic infection. We propose a hypothesis to explain the early events in the genital transmission of SIV.

Mechanism of genital transmission of SIV: a hypothesis based on transmission studies and the location of SIV in the genital tract of chronically infected female rhesus macaques.

Sergio A. Bencosme

Papers

Electron microscope observations on Langerhans cells in the cervix.