Chinese Rhesus Research Articles

Recombinant Modified Vaccinia Virus Ankara Expressing the Spike Glycoprotein of Severe Acute Respiratory Syndrome Coronavirus Induces Protective Neutralizing Antibodies Primarily Targeting the Receptor Binding Region

Immunization with a killed or inactivated viral vaccine provides significant protection in animals against challenge with certain corresponding pathogenic coronaviruses (CoVs). However, the promise of this approach in humans is hampered by serious concerns over the risk of leaking live severe acute respiratory syndrome (SARS) viruses. In this study, we generated a SARS vaccine candidate by using the live-attenuated modified vaccinia virus Ankara (MVA) as a vector. The full-length SARS-CoV envelope Spike (S) glycoprotein gene was introduced into the deletion III region of the MVA genome. The newly generated recombinant MVA, ADS-MVA, is replication incompetent in mammalian cells and highly immunogenic in terms of inducing potent neutralizing antibodies in mice, rabbits, and monkeys. After two intramuscular vaccinations with ADS-MVA alone, the 50% inhibitory concentration in serum was achieved with reciprocal sera dilutions of more than 1,000- to 10,000-fold in these animals. Using fragmented S genes as immunogens, we also mapped a neutralizing epitope in the region of N-terminal 400 to 600 amino acids of the S glycoprotein (S400-600), which overlaps with the angiotensin-converting enzyme 2 (ACE2) receptor-binding region (RBR; S318-510). Moreover, using a recombinant soluble RBR-Fc protein, we were able to absorb and remove the majority of the neutralizing antibodies despite observing that the full S protein tends to induce a broader spectrum of neutralizing activities in comparison with fragmented S proteins. Our data suggest that a major mechanism for neutralizing SARS-CoV likely occurs through blocking the interaction between virus and the cellular receptor ACE2. In addition, ADS-MVA induced potent immune responses which very likely protected Chinese rhesus monkeys from pathogenic SARS-CoV challenge.

Simple sequence repeat (SSR) polymorphisms for colony management and population genetics in rhesus macaques (Macaca mulatta).

Cross-species amplification of 72 SSR (predominantly tetranucleotide) loci from the DNA of six rhesus macaques of diverse regional origins was conducted using human primers for the polymerase chain reaction (PCR). Thirteen of these primer pairs, which consistently and unambiguously amplified polymorphic fragments from these six samples and which exhibited Mendelian properties, were also used to amplify SSR loci for 176 male rhesus macaques that are founders of six different captive breeding colonies. These include four groups of macaques originating in India and one group of macaques each that originated in China and Thailand. Gene diversity based on the SSR loci provided a reliable estimate of average heterozygosity but was between two and four times higher than that for 9 protein coding loci. Based on the SSR loci, Chinese rhesus were more genetically diverse and unique than were rhesus from India or Thailand, a conclusion not consistent with data based on protein coding loci. The six most informative SSR loci are unlinked and provide probabilities of single parent exclusion and genetic identity exceeding 0.99 and one in one million, respectively, both of which are reasonable standards for colony management purposes.