Streptococcal Immunity Is Constrained by Lack of Immunological Memory following a Single Episode of Pyoderma

The immunobiology underlying the slow acquisition of skin immunity to group a streptococci (gas),is not understood,but attributed to specific virulence factors impeding innate immunity and significant antigenic diversity of the type-specific m-protein,hindering acquired immunity. we used a number of epidemiologically distinct gas strains to model the development of acquired immunity. we show that infection leads to antibody responses to the serotype-specific determinants on the m-protein and profound protective immunity; however,memory b cells do not develop and immunity is rapidly lost. furthermore,antibodies do not develop to a conserved m-protein epitope that is able to induce immunity following vaccination. however,if re-infected with the same strain within three weeks,enduring immunity and memory b-cells (mbcs) to type-specific epitopes do develop. such mbcs can adoptively transfer protection to naïve recipients. thus,highly protective m-protein-specific mbcs may never develop following a single episode of pyoderma,contributing to the slow acquisition of immunity and to streptococcal endemicity in at-risk populations. © 2016 pandey et al.