Cell surface molecules involved

The amino sugar inhibition pattern su ested two new lines of inquiry which led to the definition of macrophage cell surface molecules involved in the clearance of apoptotic neutrophils. 

CD 18, CD25, CD44, CD45, and HLA class I and II molecules on the surface of human T lymphocytes. The antibodies deplete circulating lymphocytes by direct cytotoxicity (both complement and cell-mediated) and block lymphocyte function by binding to cell surface molecules involved in the regulation of cell function. 

Antonia, S. J., Uchida, J., Cohen, S. and Cohen, M. C. (1989). Attachment of tumor cells to endothelial monolayers detection of surface molecules involved in cell-cell binding. Clin. Immunol. Immunopathol. 53, 281-296. 

Adherence to host tissue is achieved by a combination of specific and non-specific mechanisms. Specific adherence mechanisms include ligand-receptor interactions, while non-specific mechanisms include electrostatic forces, aggregation and cell surface hydrophobicity. Non-specific interactions are the primary interaction (occurring over longer distances) involved in the adherence process and are reversible. However, non-specific adherence is consequently deemed irreversible as a result of specific mechanisms that involve the ability of the yeast to recognize a variety of host cell receptors/ ligands using cell surface molecules. 

The selection of cell-targetingpeptides may involve targeting a known cell surface molecule or screening whole cells without a priori knowledge of the chemical nature of the cell surface. The latter approach can lead to identification of hitherto unknown cell surface receptors or target molecules. 

Human leukocyte antigens are polymorphic cell-surface molecules that are intimately involved in the regulation of the immune response. The antigens are encoded by a series of closely linked genes known as the major histocompatibility complex (MHC), which is located on the short arm of chromosome 6 (BIO). The complex extends over approximately 4000 kilobases or 4 x 10 nucleotides and contains three distinct subregions known as class I, class II, and class III (T19) (see Fig. 1). 

In addition to the recently isolated cell surface receptor proteins for cell adhesion proteins (10-13), it has become clear that most cell adhesion molecules also recognize other cell surface molecules. Most cell adhesion proteins possess discrete binding sites for collagen, heparin, and ganglioside (or other glycolipids). The avidity of most cell adhesion proteins for one or more species of collagen and the involvement of this interaction in cell adhesion has been reviewed (1) and we will treat this area more thoroughly in a subsequent section. 

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