Study on the immunogenicity of Hib-TT in DTaP-Hib combined vaccine

To investigate the immunogenicity of the Hib-TT in the DTaP-Hib combined vaccine,namely dosage,immune persistence and compatibility.The DTaP-Hib combined vaccine with different dosages of Hib-TT and the monovalent Hib-TT with 2.5μg dosage were injected to the mice.Blood samples were taken on the 1,2,4,6,8,10 week after the last injection for testing the antibodies against Hib polysaccharide.The Hib-TT with different dosages in the DTaP-Hib combined vaccine are all appear the good immunogenicity and immune persistence in mice.The antibody positive rates are all 100%.And the higher dosage,the higher antibody titer against Hib polysaccharide.Antibody titer against the Hib polysaccharide in the monovalent Hib-TT with 2.5μg dosage is statistically higher than the DTaP-Hib combined vaccine with the same dosage at the 1-2th week after the last injection(P0.05) and at the 4-10th week there was no difference from each other(P0.05).Antibody titer against Hib polysaccharide in the monovalent Hib-TT with 2.5μg dosage is lower than that of DTaP-Hib combined vaccine with the 5.0μg dosage and there was no difference at the 1th week(P0.05) and difference at the 2-10th week from each other(P0.01).The Hib-TT in the DTaP-Hib combined vaccine has the good immunogenicity and immune persistence in mice.The antigen interference of Hib-TT by combineding to DTaP is transitory.