How vaccines work: immune effector mechanisms and designer vaccines

ABSTRACT

Introduction: Three major advances have led to increase in length and quality of human life: increased food production, improved sanitation and induction of specific adaptive immune responses to infectious agents (vaccination). Which has had the most impact is subject to debate. The number and variety of infections agents and the mechanisms that they have evolved to allow them to colonize humans remained mysterious and confusing until the last 50 years. Since then science has developed complex and largely successful ways to immunize against many of these infections.

Areas covered: Six specific immune defense mechanisms have been identified. neutralization, cytolytic, immune complex, anaphylactic, T-cytotoxicity, and delayed hypersensitivity. The role of each of these immune effector mechanisms in immune responses induced by vaccination against specific infectious agents is the subject of this review.

Expertopinion: In the past development of specific vaccines for infections agents was largely by trial and error. With an understanding of the natural history of an infection and the effective immune response to it, one can select the method of vaccination that will elicit the appropriate immune effector mechanisms (designer vaccines). These may act to prevent infection (prevention) or eliminate an established on ongoing infection (therapeutic).

Literature search: The primary literature source is Pub Med. Secondary source is Wikipedia.

KEYWORDS:

• Vaccines
• immune effector mechanisms
• toxin neutralization
• receptor blockade
• anaphylactic reactions
• antibody-mediated cytolysis
• immune complex reactions
• T-cell-mediated cytotoxicity
• delayed hypersensitivity

Article highlights

• Specific immune effector mechanisms are directed to defend against infectious agents

• Vaccines should be designed to elicit the appropriate mechanism for each infection

• Vaccines can be used not only to prevent, but also to treat infections

• Antibodies can both neutralize toxins and block receptor-ligand interactions

• Cytotoxic lymphocytes are effective on infections of epithelial cells and on cancer cells

• Delayed hypersensitive is effective for tuberculosis, leprosy, syphilis and fungal infections

• Effective approaches for inducing delayed hypersensitivity need to be developed

Declaration of interest

The author has no relevant affiliations or financial involvement with any organization on entity with a financial interest in of financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received of pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.