Objective    To develop a new

Streptococcus pneumoniae

vaccine which is safe

effective and easy to produce.  The efficacy of this vaccine will be approached in BALB/c mice.    Methods    HID39 was a heat-inactivated vaccine candidate origin from standard strain D39

which lost virulence but kept immunogenesis. Mice were divided into negative group

subcutaneous group and intranasal group

and were vaccinated HID39. Antibodies and subclasses were detected by ELISA. And mice were challenged with different strains to evaluate the effect of vaccine.      R

esults    After immunization with HID39

the mice had the serum IgG titers reaching 12 800±8 744 in subcutaneous group and 4 032±1 652 in intranasal group

while their saliva IgA titers reaching 400±197 in the later group but undetectable in the former group. IgG1

IgG2a and IgG2b were the main antibody subclasses and IgG3 was undetectable. The colonization of TIGR4 in the nasal

lung and brain were significantly decreased

and there were the least amount of nasal immunity. Importantly

this vaccine candidate provided efficient active protection against fetal intranasal and intraperitoneal infections with D39 strain and 2 clinical strains of serotype 6B and 3. The survival percent of intranasally immunized mice was about 50%

and the survival percent of passive protection of antibody was more than 50%.     Conclusion    HID39 is a successful vaccine and can induce immune response against pneumococcal infections in mice.