[1]Nwigube, M. E., *2Eya, C. P., 1Agu, C. C., 1Ogunfolakan, O. O., 2Ebhodaghe, F.,
1,3Amadi, O. V., and 1Abelekum,J. T.
1Department of Medical Laboratory Science, College of Medicine and Health Science, Afe Babalola University, Ado-Ekiti, Ekiti State, Nigeria
2Department of Environmental Health Science, Faculty of Health Science, National Open University of Nigeria, Cadastral Zone, Nnamdi Azikiwe Expressway, Jabi, Abuja, Nigeria
3Department of Medical Laboratory Science, College of Medicine and Health Science, Venite University, Ado-Ekiti, Ekiti State, Nigeria
*Correspondence to pceya@noun.edu.ng; +234 (813) 847-6175
ORCID: https://orcid.org/0009-0007-9591-4807
Abstract:
Vaccines are biological preparations that stimulate the immune system to prevent infectious disease without causing illness. By delivering weakened or inactivated pathogens, purified antigens, or genetic material encoding specific proteins, vaccines induce antibody production and generate memory B and T cells, enabling rapid, protective responses upon later exposure. Vaccination is among the most effective public health measures, leading to the eradication of smallpox in human and rinderpest in ruminants, and control of many infectious diseases. Advances such as recombinant and mRNA platforms have broadened applications to emerging infections and cancer immunotherapy. Adjuvants enhance vaccine immunogenicity, particularly in subunit and inactivated formulations. They activate innate immune pathways, including pattern recognition receptors (PRRs) such as Tolllike receptors (TLRs), triggering inflammatory signaling and cytokine release. This promotes recruitment and maturation of antigen-presenting cells, especially dendritic cells, improving antigen presentation and T-cell activation. Adjuvants also shape adaptive immunity by directing T-helper cell polarization and strengthening cytotoxic T-lymphocyte responses. Major adjuvant classes include aluminum salts (alum), which primarily elicit strong antibody (Th2) responses; emulsion-based systems such as MF59 and AS03, which enhance antigen uptake and promote balanced humoral and cellular immunity; and TLR agonists such as monophosphoryl lipid A and CpG oligodeoxynucleotides, which drive Th1-biased responses. Saponin-based and liposomal formulations further augment both antibody and cellular immunity, supporting vaccines against complex pathogens and cancer. Ongoing advances in molecular immunology and nanotechnology are enabling next-generation adjuvants designed to achieve precise, durable, and safe immune protection, underscoring their central role in future vaccine development and global disease prevention. Continue reading “A review of vaccine adjuvants in modern immunology: Mechanisms, classes, and advances in next-generation vaccine design”