Biological Differences in rAAV Transduction of Airway Epithelia in Humans and in Old World Non-human Primates

Non-human primates (NHPs) are considered to be among the most relevant animal models for pre-clinical testing of human therapies, on the basis of their close evolutionary relatedness to humans in terms of organ cell biology and physiology. In this study, we sought to investigate whether NHP models accurately reflect the effectiveness of recombinant adeno-associated virus (rAAV)-mediated gene delivery to the airway in humans. In order to do this, we utilized an identical model system of differentiated airway epithelia from Indian Rhesus monkeys and from humans, cultured at an air-liquid interface (ALI). In addition to assessing the biology of rAAV-mediated transduction for three serotypes, we characterized the bioelectric properties as a reference for biological similarities and differences between the cell cultures from the two species. Our results demonstrate that airway epithelia from NHPs and humans have very similar Na(+) and Cl(-) transport properties. In contrast, rAAV transduction of airway epithelia of NHPs demonstrated significant differences to those in humans with regard to the efficiency of apical and/or basal transduction with three rAAV serotypes (AAV1, AAV2, AAV5). These findings suggest that the IndianRhesusmonkey may not be the best model for preclinical testing of rAAV-mediated gene therapy to the airway in humans.

Molecular beacon genotyping for globoid cell leukodystrophy from hair roots in the twitcher mouse and rhesus macaque

Rapid and accurate genotype determination is ideal for the maintenance of breeding colonies of laboratory animal models of genetic disease. The rhesus macaque and murine (twitcher) models of globoid cell leukodystrophy have a dinucleotide deletion or single nucleotide substitution, respectively, which abolish ceramide beta-galactosidase activity and are authentic models of Krabbe disease. We report a molecular beacon PCR assay for each species which allows unambiguous determination of the genotype in under 4h. The assay works reliably with DNA extracted from hair roots using Chelex-100 in a 20 min, 100 degrees C incubation. We demonstrate that genotyping from hair roots is a preferred alternative to collecting blood or tissue for DNA extraction because it reduces animal distress, uses an inexpensive reagent, and is simpler and faster. Following amplification on a standard thermocycler with a 96-well plate format, these molecular beacon assays can be read on a standard laboratory fluorescent plate reader, eliminating the need to use a real-time thermocycler or to open the plate for subsequent restriction enzyme digestion and gel electrophoresis. The multiplexed ratio of fluorescence from wild-type- and mutant-specific beacons reporting at 560 nm and 535 nm wavelengths is distinct for each genotype.

Serologic responses to Mycobacterium leprae-specific phenolic glycolipid-I antigen in sooty mangabey monkeys with experimental leprosy

Four pairs of sooty mangabey monkeys (Cercocebus atys) were inoculated with serial, 10-fold dilutions of Mycobacterium leprae. The highest-dose pair received 4.8 X 10(10) M. leprae. Serum samples were obtained and clinical signs of leprosy were recorded at intervals of 35 months. Longitudinal serum samples were assayed by an ELISA method for the presence of IgG and IgM antibodies to the M. Leprae-specific phenolic glycolipid-I (PGL-I) antigen. In general, the onset of disease symptoms paralleled the number of M. leprae inoculated, but the ultimate course of disease depended upon individual animal susceptibility. Both IgG and IgM anti-PGL-I isotypes were observed in variable levels and patterns, related to the disease stage, among the eight mangabeys. The data suggest that high IgG and low IgM anti-PGL-I levels correlated with less severe disease; whereas initial high IgM titers and/or rising or sustained high IgM titers, especially together with low IgG anti-PGL-I titers, preceded or corresponded to periods of progressive leprosy. The results show that IgG and IgM anti-PGL-I antibodies can be present in significant titers among mangabeys early after infection with M. leprae. It appears likely that the relative levels of these anti-PGL-I isotypes may be correlated with the susceptibility of individual animals to the development of lepromatous leprosy.