ABSTRACT
Objective To investigate whether capsular polysaccharides of Streptococcus pneumoniae serotypes 6A and 6B contained in 13-valent pneumococcal conjugate vaccine ( PCV13 ) could induce cross- protective antibodies against newly discovered serotypes 6C and 6D and the differences between them. Methods New Zealand rabbits were radomly divided into three groups and respectively muscularly administrated with three doses of PCV13, PCV6A and PCV6B on days 0, 14 and 28. PCV6A and PCV6B were conjugates of capsular polysaccharides of serotypes 6A and 6B chemically coupled with diphtheria toxin mutant CRM197. Serum samples were collected on days 0 and 35. Enzyme-linked immunosorbent assay (ELISA) recommended by World Health Organization (WHO) was used to quantitatively measure serotype-specific antibodies to capsular polysaccharides of serotypes 6A, 6B, 6C and 6D. Opsonophagocytosis assay ( OPA) of WHO pneumococcal serology reference laboratory was used to determine antibody functional activities targeting serotypes 6A, 6B, 6C and 6D. Results Immunization rabbits with PCV13 induced the secretion of antibodies to capsular polysaccharides of serotypes 6A and 6B. These antibodies were able to not only cross-react with capsular polysaccharides of serotypes 6C and 6D but also recognize and bind to target Streptococcus pneumoniae serotypes 6A, 6B, 6C and 6D, resulting in the activation of complements and further phagocytosis of target bacteria by differentiated HL60 cells. Bactericid-al titers were largely even among these serotypes except for serotype 6D which was slightly lower. PCV6A could induce antibody against capsular polysaccharide of serotype 6A, which was able to cross-react with capsular pol-ysaccharides of serotypes 6B, 6C and 6D and showed higher bactericidal titers to serotypes 6A, 6B and 6C over serotype 6D. PCV6B could induce antibody against capsular polysaccharide of serotype 6B, which was able to cross-react with capsular polysaccharides of serotypes 6A, 6C and 6D and showed higher bactericidal titers to se-rotypes 6A, 6B and 6C over serotype 6D. Antibody concentrations and bactericidal titers specific to serotypes 6A, 6B, 6C and 6D were significantly increased following immunization with PCV13, PCV6A or PCV6B (P<0. 01). Conclusion PCV13 containing pneumococcal serotypes 6A and 6B induced antibodies against capsular polysaccharides of serotypes 6A and 6B in New Zealand rabbits, which were able to cross-react with capsular polysaccharides of serotypes 6C and 6D and provide cross-protection to bacteria of serotypes 6C and 6D. Both serotypes of 6A and 6B contained in PCV13 contributed to the induction of cross-protective antibodies, especially to serotype 6C.
ABSTRACT
Marburg virus (MARV) is a lethal virus that causes fatal hemorrhagic fever.It belongs to the Filoviridae family which also includes Ebola virus.MARV is similar to Ebola virus in structure and infection mechanism.Moreover,the diseases caused by them have similar clinical symptoms.However,researches on MARV are less than those on Ebola virus.In this review,we focus on the viral structure,especially the structure of MARV glycoprotein (GP) which determines its infectivity,functions of MARV GP as well as protective antibodies and vaccines against this protein.
ABSTRACT
Aim To explore the function of immune modulation of anti-HBV iRNA in patients with chronic hepatitis B(CHB) Methods Peripheral blood lymphocyte iRNA was prepared from anti-HBs positive human body with HBV complete clearance after HBV infection(h-iRNA). The effect of h-iRNA on HBV specific lymphocyte proliferative response of peripheral lymphocyte from patients with CHB was observed by using MTT method and was compared with that by HBV specific iRNA from animal immunized only by HBsAg(a-iRNA).Results Both h-iRNA and a-iRNA increased the level of peripheral lymphocyte proliferative response to HBsAg in patients with CHB to some degree. In group of HBcAg, only h-iRNA showed its enhancement of HBcAg specific lymphocyte proliferative response.Conclusions h-iRNA can increase HBV specific lymphocyte proliferative response in patients with CHB and the function of increasing HBcAg specific lymphocyte proliterative response contributes to HBV clearance .