Importance of Cry Proteins in Biotechnology: Initially a Bioinsecticide, Now a Vaccine Adjuvant

Abstract

A hallmark of Bacillus thuringiensis bacteria is the formation of one or more parasporal crystal (Cry) proteins during sporulation. The toxicity of these proteins is highly specific to insect larvae, exerting lethal effects in different insect species but not in humans or other mammals. The aim of this review is to summarize previous findings on Bacillus thuringiensis, including the characteristics of the bacterium, its subsequent contribution to biotechnology as a bioinsecticide due to the presence of Cry proteins, and its potential application as an adjuvant. In several studies, Cry proteins have been administered together with specific antigens to immunize experimental animal models. The results have shown that these proteins can enhance immunogenicity by generating an adequate immune response capable of protecting the model against an experimental infectious challenge, whereas protection is decreased when the specific antigen is administered without the Cry protein. Therefore, based on previous results and the structural homology between Cry proteins, these molecules have arisen as potential adjuvants in the development of vaccines for both animals and humans. Finally, a model of the interaction of Cry proteins with different components of the immune response is proposed.

Multiple cry Genes in Bacillus thuringiensis Strain BTG Suggest a Broad-Spectrum Insecticidal Activity

“…The different classes of B. thuringiensis Cry toxins bind to various receptors (cadherins, aminopeptidases, alkaline peptidases, ATP-binding transporter proteins) and therefore bioinsecticide preparations containing B. thuringiensis strains have specific toxicity against certain pest groups [ 23 , 26 ]. Thus, the bioinsecticide formula based on B. thuringiensis ssp.…”

Identification and functional characterization of eight novel tpp family genes from Bacillus thuringiensis

“…Bacillus thuringiensis (Bt) is a ubiquitous entomopathogenic bacterium, and Bt‐based products are the most successful microbial insecticides to date 1 . A characteristic of this bacterium is the production of one or more parasporal crystal (Cry) proteins during sporulation 2 . The Cry protein is the most widely used and diverse family of Bt insecticidal proteins.…”

“…1 A characteristic of this bacterium is the production of one or more parasporal crystal (Cry) proteins during sporulation. 2 The Cry protein is the most widely used and diverse family of Bt insecticidal proteins. The lethal toxicity of these proteins is highly specific to different invertebrates, such as insect pests, nematodes, mites, and some protozoa 3 ; some classes are specifically cytotoxic to human cancer cells 4 but not to humans or other mammals.…”

Transgenic maize inbred lines expressing high levels of Bacillus thuringiensis vegetative insecticidal protein (Vip3Aa86) offer effective control of maize stem borer (Chilo partellus)

“…It is estimated that average production can be increased by at least 14% if such predation by insects is eliminated (Falak 2003). A soil bacterium, Bacillus thuringiensis, forms parasporal crystal proteins belonging to several structural groups (Crickmore et al 2021) during sporulation that contained δ-endotoxins (Maria Cristina Gonzalez-Vazquez et al 2021). Proteins belonging to the Cry family are the main agents used to produce plant resistance against corn borer and are effectively used in numerous other crops (Viktorov 2015).…”