Experimental and molecular predictions of the adjuvanticity of snail mucin on hepatitis B vaccine in albino mice

Although aluminum-containing adjuvants are widely used in human vaccination due to their excellent safety profile, they exhibit low effectiveness with many recombinant antigens. This study investigated the adjuvanticity of snail mucin with recombinant Hepatitis B Vaccine (rHBsAg). Twenty-five (25) female mice distributed unbiasedly into 5 groups were used in the study and were administered different rHBsAg/Mucin formulation at 7 days intervals. Blood samples were collected a day following the administration for analysis. The results of liver function and body weight analysis were indications that snail mucin had no adverse effect on the mice. The treatment group (administer mucin and rHBsAg) showed significantly (P<0.05) higher mean titres of anti-HBsAg antibodies when compared with the negative controls and the positive control administered with two doses of rHBsAg after the boost doses (day 28). Furthermore, a comparable immune response to positive control administered with three doses rHBaAG was recorded. In silico prediction, studies of the protein-protein interaction of a homology modelled snail mucus protein and HBsAg gave an indication of enhanced HBV antigen-antibody interaction. Therefore, this study has shown that snail mucin possesses some adjuvant properties and enhances immune response towards rHBsAg vaccine. However, there is a need for further molecular dynamics studies to understand its mechanism of action.

Effectiveness of recombinant hepatitis B vaccine with/without the passive hepatitis B immunoglobulin vaccine in babies whose mothers are hepatitis B surface antigen positive in a private missionary hospital

Background: Hepatitis B infection is a potentially life-threatening liver infection. The burden is more in the less developed countries. Vaccination is the most cost-effective way to control hepatitis B virus (HBV) infection and its chronic complications globally. Active-passive immunoprophylaxis using hepatitis B immunoglobulin combined with recombinant hepatitis B vaccine is recommended for infants of women with chronic HBV infection. This study aimed to determine the effectiveness of the hepatitis B recombinant vaccine alone or combined with hepatitis B immunoglobulin.Methods: The study was a prospective longitudinal study. Patients were selected using a convenient sampling technique. The study spanned between 1 January 2017 and 31 December 2018. Data analysis was with SPSS version 21.Results: The unit recorded 1690 deliveries during the recruitment period, 70 eligible patients were recruited thus giving an incidence of 4.1%. 74.3% of the recruited patients were HBeAg negative while 25.7% were HBeAg positive. 52.9% of the babies had only recombinant HB recombinant vaccine while 47.1% had combined hepatitis B immunoglobulin and the recombinant vaccine at birth. The HBeAg status of mothers played a significant factor in the HBsAg positivity of babies two months after the completion of immunoprophylaxis against HBV.Conclusions: Giving recombinant HBV vaccine in combination with the HBV immunoglobulin is the standard practice, this may not always be so based on the findings from this study. However, the population studied is too small to make a categorical statement thus a larger population needs to be studied.

P318 Intra-dermal with topical imiquimod pre-treatment versus intra-muscular hepatitis B vaccination in inflammatory bowel disease patients: a double-blind randomized controlled trial

Background Patients with inflammatory bowel disease (IBD) are often immunocompromised and at risk of various opportunistic infections including viral hepatitis. Vaccination is recommended to prevent hepatitis B infection, but efficacy with conventional intra-muscular hepatitis B vaccination in IBD patients is suboptimal. Intra-dermal vaccination has been shown to be an effective way in augmenting immune response in poor vaccine responders. In addition, topical imiquimod, a synthetic agonist of toll-like receptor 7, has been shown to further boost the immunogenicity when applied to the injection site before intra-dermal vaccination. Our study compared the efficacy of intra-dermal hepatitis B vaccination with topical imiquimod with conventional intra-muscular hepatitis B vaccination in IBD patients. Methods This is a double-blind, randomized-controlled trial. IBD patients with no evidence of active or past infection nor history of vaccination i.e. negative serology to all HBsAg/Anti-HBc/Anti-HBs were recruited. They were randomized in 1:1 ratio to receive either intra-dermal recombinant hepatitis B vaccine with topical imiquimod pre-treatment to site of injection (ID) or intra-muscular recombinant hepatitis B vaccine with topical aqueous cream (IM). Same dose (20mcg) of vaccine (Engerix B, Glaxo Smith Klein) was administered to both groups at 0, 1, 6 month. The primary outcome was the sero-protection rate at 12-month, defined as percentage of recruited subjects with anti-HBs titre ≥ 10 mIU/mL. Results 104 patients (mean age 46; 68% male; 50% Crohn’s and 50% UC) were enrolled, with 53 received ID and 51 received IM vaccine. The percentage of patients using steroids, immunomulators and biologics at the time of randomization was 15, 55 and 22 %, respectively. Baseline demographic, disease characteristic, and laboratory parameter were comparable between the ID and IM groups. Sero-protection rate at 12-month was significantly higher in the ID arm compared to the IM arm (91% vs. 69%, P=0.005; Figure). Percentage of good responders at 12 month (anti-HBs titre &gt; 100 mIU/mL) was also higher in the ID arm than in the IM (77% vs 59%, P=0.042). Multivariate analysis showed that use of ID vaccine (OR 4.45, 95% CI 1.40-14.47) and a higher albumin level (OR 1.30, 95% CI 1.06-1.58) are associated with better sero-protection rate. There was no significant difference in adverse effects reported in (64% in ID vs 55% in IM; Table). Conclusion ID hepatitis B vaccination with topical imiquimod is safe and offers superior seroprotection against hepatitis B among IBD patients.

Abated immune responses against recombinant hepatitis-b vaccine by chitin in mice

Abated immune responses against recombinant hepatitis-b protein vaccine by chitin in miceMajority of recombinant protein vaccines employ alum-based adjuvants to boost their immunogenicity in subjects. However, the safe-profiled alum-based adjuvants demonstrate relative ineffectiveness with these recombinant vaccines. This work investigated the adjuvant potential of chitin with recombinant Hepatitis-B protein vaccine (HBsAg) and its possible toxicological effects. Six to eight weeks old female albino mice, which were randomly and equally distributed into five groups were used for this study. Blood collection was done before each vaccination schedule and the samples were used for analysis. Results revealed that IgG and IgG1 titres of mice administered 2 doses of HBsAg-Chitin formulation was significantly (p < 0.05) lower than those administered 3 doses of HBsAg and was not significantly (p > 0.05) higher than those administered 2 doses of HBsAg. However, a progressive increase in the anti-HBsAg titres in mice that received the HBsAg-Chitin formulation was observed as days came by. Activities of alanine and aspartate aminotransferases of all experimental groups, including their liver weights, inferred that the HBsAg-Chitin formulation exert no toxic effect on the liver. The findings of this research revealed that chitin demonstrated a relatively unimpressive adjuvant activity with the recombinant hepatitis-B protein vaccine.GRAPHICAL ABSTRACT