and L.W. the Pyrroloquinoline quinone production of secret IgA antibodies and IgG antibodies and enhances the protective efficacy of the split influenza vaccine by intranasal administration. Furthermore, co-administration of 7DW8-5 with the split influenza vaccine significantly reduces the computer virus shedding in the upper and lower respiratory tract after lethal challenge. Our results demonstrate that 7DW8-5 is usually a novel mucosal adjuvant for the split influenza vaccine. 0.05 was considered to indicate a statistically significant difference. 3. Results 3.1. 7DW8-5 Signifiantly Increases the Mucosal and Systemic Immunogenicity of the Split Influenza Vaccine by Intranasal Administration The mice were immunized twice at a two-week interval, and the nasal wash, BALF, and sera were collected at Day 14 after the second immunization for the IgG and Pyrroloquinoline quinone IgA antibody detection. The results show that 1 g 7DW8-5 or 10 g 7DW8-5 per dose both significantly increased the titers of the IgA antibodies in the nasal wash and BALF and IgG antibodies in sera compared to the vaccine alone (Physique 1ACC), although the effect of 10 g 7DW8-5 per dose was better than that of 10 g 7DW8-5 per dose by intranasal immunization. Furthermore, the 10 g 7DW8-5 induced a little higher IgG antibody level than that of Poly(I:C) in sera, although these two groups had no significant difference (Physique 1C). Pyrroloquinoline quinone These results demonstrate that 7DW8-5 could enhance the mucosal and CSF3R systemic immune responses of the inactivated influenza vaccine by intranasal administration. Open in a separate window Physique 1 Virus-specific secretory IgA (S-IgA) titers in the respiratory tract and IgG in sera induced by intranasal co-administration of 7DW8-5 with the split inactivated influenza vaccine. Six-week-old BALB/c mice were intranasally immunized with the indicated immunogens (20 L total, 10 L/nostril) twice with a two-week interval between immunizations. Four mice were used per group. Nasal wash (NW) and bronchoalveolar lavage fluid (BALF) samples were collected two weeks after the last immunization to measure virus-specific secretory IgA and IgG antibody titers. The virus-specific IgA and IgG titers were determined by use of an ELISA with inactivated CA07 computer virus as the coating antigen. The OD was measured at a wavelength of 405 nm. The antibody titer was defined as the reciprocal of the highest dilution that produced an OD405 0.1 after correcting based on the negative serum control. The values are the means SD of the four individual antibody titers per group. (A) Virus-specific IgA antibody titers in the NWs induced by intranasal co-administration of 7DW8-5 with the split inactivated influenza vaccine. (B) Virus-specific secretory IgA antibody titers in the BALFs. (C) Virus-specific IgG antibody titers in sera. ** 0.01. 3.2. 7DW8-5 Enhances the Protective Efficacy of the Influenza Vaccine against Lethal Challenge To evaluate the effect of 7DW8-5 around the protective efficacy of the influenza vaccine by intranasal inoculation, we immunized the mice twice with 1 g or 10 g per dose 7DW8-5 at a two-week interval; the immunized mice were challenged with 10 MLD50 MA-CA04 computer virus. The body weight and survival were monitored every day for 14 days. In the PBS group (black line), the 1 g 7DW8-5 group (red line), the 10 g 7DW8-5 group (pink line), and the vaccine-alone group (blue line), body weight decreased after computer virus challenge, and all mice died by day 6 (Physique 2). In contrast, in the vaccine + 10 g 7DW8-5 group (green line) and vaccine + Poly (I:C) (gray line), all the immunized mice survived after lethal challenge. A total of 50% of the mice immunized with vaccine + 1 g 7DW8-5 group were guarded from lethal contamination, and the body weight of the survival mice presented a substantially decreased. The body weight loss of the mice immunized with vaccine plus 10 g 7DW8-5 or vaccine plus Poly(I:C) after the challenge was also observed, but it was significantly less than that in vaccine plus 1 g 7DW8-5 group (Physique 2A). These results show that 7DW8-5 could enhance the protective efficacy of the split influenza vaccine by intranasal Pyrroloquinoline quinone immunization, and the effect of 7DW8-5 as a mucosal adjuvant is usually dose-dependent. Open in a separate window Physique 2 Body weight change and survival rate of the immunized mice with the split inactivated influenza vaccine plus 7DW8-5 by intranasal administration after a lethal challenge by MA-CA04 computer virus. Six-week-old BALB/c mice were intranasally immunized with the indicated immunogens (20 L total, 10 L/nostril) twice with a two-week interval between immunizations. Four mice were used per group. Three weeks after the.