Experiments to isolate and characterize rhesus macaque myeloid alpha-defens
ins (RMADs) were conducted, Seven RMAD peptides were isolated and sequenced
, and the cDNAs encoding six of these peptides and one other alpha-defensin
from bone marrow were also characterized. Four of the RMADs were found to
be highly similar to human neutrophil alpha-defensins HNP-1 to HNP-3, while
the remaining four peptides were much more similar to human enteric alpha-
defensin HD-5. Two alpha-defensin pairs differed only by the presence or ab
sence of an additional arginine at the amino termini of their mature peptid
es, indicative of alternate posttranslational processing, The primary trans
lation products of RMAD-1 to -8 are 94- and 96-amino-acid prepropeptides th
at are highly similar to those of human alpha-defensins. Immunolocalization
experiments revealed a granular cytoplasmic pattern in the cytoplasms of n
eutrophils, indistinguishable from the pattern observed after immunostainin
g of human myeloid alpha-defensins in polymorphonuclear leukocytes, Each of
the purified peptides was tested for its in vitro activities against Staph
ylococcus aureus 502a, Listeria monocytogenes EGD, Escherichia coil ML35, a
nd Cryptococcus neoformans 271A. Several of the peptides were microbicidal
for the gram-positive bacteria and C. neoformans at defensin concentrations
in the range of 2 to 5 mu M All of the peptides were bacteriostatic agains
t E. call, but none were bactericidal for this organism. This study is the
first to characterize the sequences and activities of alpha-defensins from
nonhuman primates, data that should aid in delineating the role of these pe
ptides in rhesus macaque host defense.