Oct 1, 1989

Structural analysis of the human immunodeficiency virus-binding domain of CD4. Epitope mapping with site-directed mutants and anti-idiotypes

The Journal of Experimental Medicine
Q J SattentauA Truneh

Abstract

The CD4 molecule, a differentiation marker expressed primarily by T lymphocytes, plays an important role in lymphocyte activation. CD4 is also the receptor for HIV. A number of recent studies have localized the high affinity binding site of the HIV envelope glycoprotein, gp120, to the NH2-terminal (V1) domain of CD4, a region with sequence and predicted structural homology with Ig kappa chain V domains (V kappa). In this report, we show that V1 bears structural similarities with V kappa regions through detailed epitope mapping of 26 CD4 mAbs. The binding sites of these mAbs were initially defined relative to one another by crossblocking analysis and were then localized to specific domains of CD4 in blocking studies with truncated, soluble CD4 proteins. The epitopes within the V1 domain were mapped in detail with a panel of 17 substitution mutants, and the specificities of several mAbs that appear to recognize very similar epitopes were examined in crossblocking studies with anti-idiotype antibodies. The location of the epitopes is consistent with a V kappa-like structure of V1. Most of the epitopes lie within regions of predicted exposed loops. A number of these epitopes span discontinuous residues in the linear sequence that l...Continue Reading

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Citations

Mentioned in this Paper

Receptors, HIV
Monoclonal Antibodies
T-Lymphocyte
CD4 Antigens
Recombinant soluble CD4
Antigenic Specificity
ERVW-1 gene
Spastic Syndrome
HIV Infections
Immunoglobulin kappa-Chains

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