Defensin Alpha 3, Neutrophil Specific (DEFa3)

DEFA1 and DEFA3 differ from each other only by their N-terminal amino acids (ala and asp, respectively). DEFA2 is identical to both except that it lacks this N-terminal amino acid.DEFA1-, DEFA2-, and DEFA3-specific antibodies depleted antiviral activity in a dose-dependent manner, particularly against viruses using CXCR4 rather than CCR5 as a coreceptor. Addition of synthetic or purified natural defensins inhibited HIV-1 replication in vitro.

Flow cytometric analysis determined that in addition to neutrophils, a small population of CD8-positive T lymphocytes harbor and secrete DEFA1, DEFA2, and DEFA3. Zhang et al. (2002) proposed that these defensins account for much of the anti-HIV-1 activity of CAF that is not attributable to beta chemokines.