IgA Inhibits Gp120-CD Binding In Serum And Saliva Of HIV-infected Patients
NEW YORK (Reuters Health) - French scientists report that IgA purified from serum and saliva from HIV-1-infected patients can inhibit the interaction between the viral envelope protein gp120 and the soluble CD4 (sCD4) receptor, a key initiating event in HIV infection.
This finding has implications for HIV vaccine development, Dr. Nadine Vincent from the University of Saint-Etienne, France and colleagues note in their report in the January 2nd issue of the journal AIDS.
In their experiments, purified serum and saliva IgA from HIV-1-infected patients reacted with peptides representing the CD4-binding domain of gp120 as well as a conserved region of gp41 (the Kennedy epitope or maltose-binding protein 24).
"Of the sera and saliva samples tested, 6/26 serum IgA and 5/25 saliva IgA inhibited the gp120-sCD4 interaction by approximately 50%," the team reports. Specifically, maltose-binding protein 24 (MBP24) affinity-purified IgA but not MBP42 affinity-purified IgA inhibited the gp120-sCD4 interaction.
"MBP24 represents a larger fragment of gp120," the team notes, adding that, recently, it has been shown that this region contains residues implicated in coreceptor binding as well.
Dr. Vincent and colleagues say further studies are needed to "evaluate the biological importance of IgA antibodies directed to the CD4-binding domain and to the Kennedy epitope."
"The identification and characterization of epitopes of the envelope protein that elicit neutralizing IgA antibodies may direct the design of vaccine protecting against mucosal transmission of HIV-1," they add.
Source: AIDS 2004;18:37-43. [ Google search on this article ]
MeSH Headings: Antigens, Viral : Biological Sciences : Biology : Genetics : Immunogenetics : Retroviridae Proteins : Viral Envelope Proteins : Viral Proteins : Viral Vaccines : HIV Antigens : CD4-Positive T-Lymphocytes : Viral Structural Proteins : Gene Products, env : HIV Envelope Protein gp120 : AIDS Vaccines : Polyproteins : Biological Sciences
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