Humoral and cell-mediated immune-responses after administration of a single-shot recombinant hepatitis B surface antigen vaccine formulated with cationic poly(l-lactide) microspheres

Abstract

The present investigations were aimed to compare the humoral and cell-mediated immune responses between recombinant hepatitis B surface antigens (HBsAg) adsorbed L-PLA microspheres (Ms) vaccine (single-shot) and marketed alum-HBsAg vaccine (two-doses). The blank cationic (cetyltrimethyammoniumbromide) microspheres were prepared by the double emulsion (w/o/w) solvent evaporation technique. The HBsAg was adsorbed onto the surface of blank cationic microspheres. These microspheres were characterized in vitro for their size, shape, adsorption-efficiency, in-process stability, and HBsAg release studies. Specific humoral immune responses (IgM and IgG) and cell-mediated immune responses (cellular-proliferation) assay including release of interferon-gamma (IFN-γ), interleukin-2 (IL-2), and nitric oxide (NO) from host’s cells stimulated with HBsAg or lipopolysaccharide (LPS)/ concanavalin A (con A) in-vitro were determined. Based on these findings, it was concluded that the single injection (using subcutaneous-route) of the polymeric microspheres produced better immune response (both humoral and cell-mediated) than two injections of a conventional alum-HBsAg vaccine. These data demonstrate high potential of polymeric microspheres for their use as a carrier adjuvant for hepatitis B vaccine.

Key words::

• Hepatitis B
• microspheres
• immunoglobulins
• lymphocyte transformation test
• Th1 cytokines
• nitric oxide

Acknowledgements

Authors are especially grateful to Dr. Esther Kooijman, (Director, Purac Biochemical Limited; Netherland) for a gift sample of PLA. We wish to acknowledge Dr. Umesh Shaligram (Serum Institute of India, Pune) and Dr. S.V. Kotbagi (Shantha Biotechnics Limited, Hyderabad; India) for a generous gift of the recombinant HBsAg. We are also thankful to Panjab University, Chandigarh, India and All India institute of Medical Sciences, New Delhi, India for providing facilities of electron microscopy (SEM &TEM).

This work was supported by AICTE, New Delhi, India for a J.R. fellowship to VS.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.