ospC Diversity in Borrelia burgdorferi

Abstract

The outer surface protein C (ospC) locus of the Lyme disease bacterium, Borrelia burgdorferi, is at least an order of magnitude more variable than other genes in the species. This variation is classified into 22 ospC major groups, 15 of which are found in the northeastern United States. The frequency distributions of ospC within populations suggest that this locus is under balancing selection. In multiple-niche polymorphism, a type of balancing selection, diversity within a population can be maintained when the environment is heterogeneous and no one genotype has the highest fitness in all environments. Genetically different individuals within vertebrate species and different vertebrate species constitute diverse environments for B. burgdorferi. We examined four important host species of B. burgdorferi and found that the strains that infected each species had different sets of ospC major groups. We found no variation among conspecific hosts in the ospC major groups of their infecting strains. These results suggest multiple niches create balancing selection at the ospC locus. May et al. 1999). Investigations of these loci can of the succeeding tick cohort, then feed on these inincrease our understanding of the dynamics of natural fected hosts in the late summer and become infected selection and the ecological interactions driving selecbefore they molt to nymphs, renewing the cycle (Andertion in natural populations. We propose that the poly- (Magnarelli et al. 1987; Burgdorfer et al. 2000). OspC is one of the first and most heavily targeted borrelial antigens by the vertebrate immune system (Wilske et al. 1986(Wilske et al. , 1993Dressler et al. 1993

An ecological approach to preventing human infection: Vaccinating wild mouse reservoirs intervenes in the Lyme disease cycle

“…These and other observations in both North America (18,40,41) and Europe (38,42,43) have led to a hypothesis about the importance of diverting larval ticks away from their major reservoir host species to achieve a lower nymphal infection prevalence. Our results are consistent with that hypothesis: there were direct relationships between mouse density and nymphal infection prevalence and between the population structure of B. burgdorferi, a proxy for evaluating reservoir host contributions (39), and nymphal infection prevalence. Extrapolation to the y intercept beyond the data range of Fig.…”

“…To investigate the differences among sites in vaccine effect, we examined the genotypes of B. burgdorferi strains at a polymorphic locus between their 16S and 23S ribosomal RNA genes (27,32). The rationale was the findings of different population structures among vertebrate taxa for LD Borrelia species in Europe (38) and for B. burgdorferi in New York (39). In other words, the strain structure of B. burgdorferi is an indicator of the relative contributions of mice and other reservoir hosts to infecting larvae (27).…”

The genetic structure of Borrelia afzelii varies with geographic but not ecological sampling scale

“…This view is supported by the finding of significant host specificity in B. burgdorferi ss, where different ospC genotypes were associated with different mammal species (Brisson & Dykhuizen, 2004). However, in the present study, we found no conclusive evidence for host specificity of ospC genotypes (although the analysis approached statistical significance in one of the regions).…”

“…The high intrapopulation diversity at ospC must be maintained by some sort of balancing selection. There is evidence that host species specificity is one important factor (Brisson & Dykhuizen, 2004), but negative frequency-dependent selection mediated by host immunity could also play a role (Dykhuizen & Brisson, 2010).…”

Biology of Infection with Borrelia burgdorferi

“…Studies of the significance of OspC type have reached contradictory conclusions. Some studies have found a correlation between OspC type and wild rodent host specificity [129], but others found no such link [130]. The OspC types of human clinical isolates have also been correlated with invasive and non-invasive phenotypes [128,131].…”