CDR-H3/C2

Definition
Complementarity-determining regions (CDRs) are hypervariable loop structures in the antigen-binding parts of antibodies and determine the specificity of antigen binding1. Improvement of antibody affinity may be obtained by site-directed mutagenesis of individual amino acid residues in the antibody CDRs1. CDR-H3/C2 is a peptide derived from the third heavy chain domain and modified by cyclization. It is capable of neutralizing HIV-1 replication1.

Discovery
CDR-H3/C2 was constructed in 1993 using sequences of mouse monoclonal antibody F58 that has the capacity to neutralize HIV-11.

Classification
CDR-H3/C2 belongs to the immunoglobulin superfamily of peptides1.

Structural Characteristics
CDR-H3/C2 is a 16 amino acid peptide with the sequence- CDLIYYDYEEDYYFDC, the ends of which are held by a disulphide bond to form a cyclic structure1.

Mode of action
CDR-H3/C2 binds effectively to HIV-1 variable region V3 and most likely preventing the interaction of HIV-1 to antibodies on the host cell1. This in turn inhibits infection of HIV into the host cell1.

Functions
CDR-H3/C2 is a neutralizing peptide for HIV-11.

References
1.Levi M, Sällberg M, Rudén U, Herlyn D, Maruyama H, Wigzell H, Marks J, Wahren B (1993). A complementarity-determining region synthetic peptide acts as a miniantibody and neutralizes human immunodeficiency virus type 1 in vitro. Proc Natl Acad Sci, 90(10), 4374-8.