Immune Response Of PPV23 Vaccine Administration On Subjects With Different Immune Status

Streptococcus pneumoniae is an important reason leading to adult and child hospitalization and even death.It can cause bacterial pneumonia,otitis media and meningitis and other serious diseases.The 23-Pneumococcal Polysaccharide Vaccine(PPV23)is made by capsular polysaccharide mixtures of 23 common serotypes,can be used for the prevention of Streptococcus pneumoniae infection on children over 2 years of age and adults.In order to investigate whether the PPV23 can elicit an immunoprotective response in specific populations,we have established three research groups at the Hongkou CDC,included healthy elderly(group C),the cured tuberculosis elderly(group A)and HIV infectors(group B).The serums of these groups was collected before and after vaccination PPV23 to conduct the opsonophagocytic assay.We found that all these groups showed remarkable bactericidal effect after vaccination,and the bactericidal effect of group C was more significant than that of the other two groups.To further explore the mechanism of the immune response to PPV23,we isolated the peripheral blood leukocytes of these three groups before and after vaccination,and analyzed the differences and changes of different cytokines by flow cytometry.We found that after vaccination,the activation of B cels in group C was obviously increased while other two groups have no significant changes.At the same time,we observed that production of plama cels increased markedly in both three groups,especially in group C.One month after vaccination,there was no significant change in memory B cells production in the group C,when there was a conspicuous increase in group A and a decrease in the group B.Finally,we examined the changes of Tfh cells(CD4 + CXCR5 +)in all groups before and after inoculation,and found that group C and group A were both higher than before,while group B did not change obviously.Based on the above results,we concluded that the PPV23 vaccine has a good immunoprotective effect in healthy elderly,cured tuberculosis elderly and HIV infectors,with the best effect among healthy elderly.And the vaccine can well activate B cells in healthy elderly people,making B cells differentiate to produce large amounts of plasma cels to provide immunoprotective effects.But it can not induce the production of memory B cells and may even make it reduces in HIV infectors,so the immune memory effect of PPV23 is not that good.Interestingly,memory B cells were observed a remarkble increase in cured tuberculosis elderly,we hypothesis that PPV23 could stimulate the helper cels generated by tuberculosis infection before to produces memory B cells,but the specific mechanism of this phenomenon is still unknown and need to be explored further.Finally,we conjecture that the B cell immune response caused by the PPV23 vaccine may require the participation of helper T cells.