Broadly neutralizing HIV-1 antibodies

The following table shows the characteristics of various HIV-1 bNAbs In addition to targeting conserved epitopes, bNAbs are known to have long variable regions on their immunoglobulin (Ig) isotypes and subclasses. When compared to non-bNAbs, sequence variability from the germline immunoglobulin isotype is 7 fold. This implies that bNAbs develop from intense affinity maturation in the germinal centers hence the reason for high sequence variability on the variable Ig domain. Indeed HIV-1 patients who develop bNAbs have been shown to have high germinal center activity as exhibited by their comparatively higher levels of plasma CXCL13, which is a biomarker of germinal center activity. Online databases like bNAber (now defunct) and LANL constantly report and update the discovery of new HIV bNAbs. == History of HIV bNAbs ==

In 1990, researchers identified the first HIV bNAb, far more powerful than any antibody seen before. They described the exact viral component, or epitope that triggered the antibody. Six amino acids at the tip of HIV's surface protein, gp120, were responsible. The first bNAb turned out to be clinically irrelevant, but in 1994 another team isolated a bNAb that worked on cells taken from patients. This antibody attached to a "conserved" portion of gp120 that outlasts many of its mutations, affecting 17/24 tested strains at low doses. Another bNAb was discovered that acted on protein gp41 across many strains. Antibodies require antigens to trigger them and these were not originally identified. Over time more bNAbs were isolated, while single cell antibody cloning made it possible to produce large quantities of the antibodies for study. Low levels of bNAbs are now found in up to 25% of HIV patients. bNAbs evolve over years, accumulating some three times as many mutations as other antibodies. Recent years have seen an increase in HIV-1 bNAb discovery. ==See also==