Search results
Results from the WOW.Com Content Network
Image of CD4 co-receptor binding to MHC (Major Histocompatibility Complex) non-polymorphic region. In molecular biology, CD4 (cluster of differentiation 4) is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR). CD4 is found on the surface of immune cells such as helper T cells, monocytes, macrophages, and dendritic cells.
Exposed on the surface of the viral envelope, the glycoprotein gp120 binds to the CD4 receptor on any target cell that has such a receptor, particularly the helper T-cell. Strains of HIV-1 have been isolated that are able to enter host cells that are CD4 negative. This CD4-independence is associated with spontaneous mutation in the env gene.
CD4-Ig works by mimicking the binding of CD4 to HIV, thereby preventing the virus from infecting T-helper cells. HIV infects T-helper cells by binding to the CD4 receptor and the co-receptor CCR5 or CXCR4. CD4-Ig binds to the viral envelope glycoprotein gp120, which is responsible for HIV binding to CD4. By binding to gp120, CD4-Ig prevents the ...
Since CD4 receptor binding is the most obvious step in HIV infection, gp120 was among the first targets of HIV vaccine research. Efforts to develop HIV vaccines targeting gp120, however, have been hampered by the chemical and structural properties of gp120, which make it difficult for antibodies to bind to it. gp120 can also easily be shed from the surface of the virus and captured by T cells ...
Each T cell can only recognize tens to hundreds of copies of a unique sequence of a single peptide among thousands of other peptides presented on the same cell, because an MHC molecule in one cell can bind to quite a large range of peptides. [2] [3] Predicting which (fragments of) antigens will be presented to the immune system by a certain MHC ...
The CD4 receptor in particular interacts with murine MHC-II following the "ball-on-stick" model, where the Phe-43 ball fits into the conserved hydrophobic α2 and β2 domain residues. [5] During binding with MHC-II, CD4 maintains independent structure and does not form any bonds with the TCR receptor.
Add 1 to 2 tablespoons lemon juice and more salt and pepper to taste. Add 1 to 2 tablespoons of the reserved pasta water at a time, if desired, to loosen the sauce. The pasta will absorb the sauce ...
HLA-A projected away from the cell surface and presenting a peptide sequence. The peptide-MHC complex presents a surface that looks like an altered self to the TCR. [11] The surface consisting of two α helices from the MHC and a bound peptide sequence is projected away from the host cell to the T cells, whose TCRs are projected away from the T cells towards the host cells.