Construction and preclinical evaluation of mmCT, a novel mutant cholera toxin adjuvant that can be efficiently produced in genetically manipulated Vibrio cholerae

• There is an urgent need for new adjuvants that are effective with mucosally administered vaccines. Cholera toxin (CT) is the most powerful known mucosal adjuvant but is much too toxic for human use. In an effort to develop a useful mucosal adjuvant we have generated a novel non-toxic mutant CT molecule that retains much of the adjuvant activity of native CT. This was achieved by making the enzymatically active A subunit (CTA) recalcitrant to the site-specific proteolytic cleavage ("nicking") required for toxicity, which was found to require mutations not only in the two residues rendering the molecule resistant to trypsin but also in neighboring sites protecting against cleavage by Vibrio cholerae proteases. This multiple-mutated CT (mmCT) adjuvant protein could be efficiently produced in and purified from the extracellular medium of CT-deleted V. cholerae. The mmCT completely lacked detectable enterotoxicity in an infant mouse model and had >1000-fold reduced cAMP inducing activity compared to native CT in a sensitive mammalian target cell system. It nonetheless proved to have potent adjuvant activity on mucosal and systemic antibody as well as cellular immune responses to mucosally co-administered antigens including oral cholera and intranasal influenza vaccines. We conclude that mmCT is an attractive novel non-toxic mucosal adjuvant for enhancing immune responses to co-administered mucosal vaccines

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Microbiology in the medical area (hsv//eng)

Nyckelord

Adjuvant

Cholera toxin

Mucosal immunity

Mucosal vaccine

cholera vaccine

cyclic AMP

immunoglobulin A

immunoglobulin G

influenza vaccine

proteinase

trypsin

bacterium antibody

immunological adjuvant

mutant protein

animal experiment

animal model

antibody blood level

Article

CD4+ T lymphocyte

CD8+ T lymphocyte

cellular immunity

cholera

controlled study

enzyme linked immunosorbent assay

flow cytometry

immune response

mouse

nonhuman

priority journal

thymocyte

Vibrio cholerae

animal

blood

chemistry

female

genetics

humoral immunity

immunology

metabolism

mutation

toxicity testing

Adjuvants

Immunologic

Animals

Antibodies

Bacterial

CD4-Positive T-Lymphocytes

CD8-Positive T-Lymphocytes

Cholera Vaccines

Immunity

Cellular

Immunity

Humoral

Immunity

Mucosal

Influenza Vaccines

Mice

Mutant Proteins

Toxicity Tests

Adjuvant

Cholera toxin

Mucosal immunity

Mucosal vaccine

enterotoxigenic escherichia-coli

b-subunit

vaccine development

recent

progress

dmlt adjuvant

etec vaccine

t-cells

immunogenicity

generation

antibodies

Immunology

Research & Experimental Medicine

lorenzo v

1994

bacterial pathogenesis

pt a

v235

p386

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