Foods, vaccines, bacteria and viruses can all stimulate our immune system to attack SARS-CoV-2

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic, primarily causes mild to moderate upper respiratory tract illness. However, some individuals with COVID-19 develop severe infections and require hospitalization.

study: Reaction of SARS-CoV-2 antibodies with other pathogens, vaccines and food antigensImage credit: Peddaranka Ramesh Babu / Shutterstock

Background

In general, exposure of the body to various pathogens triggers an immune response. Some of these immune cells, such as memory T cells and memory B cells, are retained in the body and protect against similarly pathogenic infections and exposure to cross-reactive agents. antigen future. In addition, these memory cells fight more effectively and efficiently while providing protection.

Immunologically, when humans encounter new infections, the host’s immune system activates memory T and B cells to provide protection against numerous antigens through the production of protective and cross-reacting antibodies. . For example, pre-existing memory cells generated against the common cold virus were protected from SARS-CoV-2 infection due to cross-reactive antigen binding.

Relevant to the recent pandemic, memory T cells were able to detect many fragments of spike and non-spike regions of SARS-CoV-2. This observation was based on epitope similarity to other peptide pools. coronavirusSome experienced mild or moderate symptoms, while others experienced severe infections due to pre-existing memory cells. Induced memory T cells are responsible for the large heterogeneity in human immune responses to COVID-19.

In addition to previous common cold infections, vaccination against various infectious diseases can also cause cross-reactivity to SARS-CoV-2. This may be why a child vaccinated against various bacterial and viral antigens was not susceptible to her SARS-CoV-2 infection. In addition, the elderly were considered susceptible to her COVID-19 disease, as the immunity induced via these vaccines declines with age.

Common herpesviruses proved to be low cross-reactive sources, whereas diphtheria, tetanus, and pertussis (DTaP) vaccines elicited significant cross-reactive immunity against SARS-CoV-2. did. Cross-reactivity also increases the risk of autoimmunity, namely cross-reactivity between SARS-CoV-2 antigens and human tissue antigens. Antigenic mimicry between human autoantigens and food proteins has also been reported.

About research

recently The forefront of immunology In a journal study, scientists analyzed how SARS-CoV-2 monoclonal antibodies interact with different pathogens and vaccines, especially DTaP. In addition, cross-reactivity between SARS-CoV-2 proteins and common foods consumed daily was determined. This is important because food-specific antibodies are produced when undigested food antigens enter the circulation. Cumulative cross-reactive immunity induced by peptides and food antigens, as well as those induced by vaccines, bacterial and viral infections, play important roles in protecting the body against a wide range of pathogens, including SARS-CoV-2. may have fulfilled.

The current study utilized monoclonal antibodies specific for SARS-CoV-2, as the epitopes shared between the two proteins do not exhibit immune cross-reactivity. Human IgG monoclonal antibody raised against SARS-CoV-2 spike proteinThe S1 domain and nuclear proteins of were used. Rabbit polyclonal antibodies were used to analyze responses to different food antigens.

Monoclonal antibodies were mainly used in this study. This is because it can detect one epitope per antigen, reducing the risk of cross-reactivity with other molecules. In addition, monoclonal antibodies reduce the potential for false positive cross-reactivity. A human SARS-CoV-2 nucleoprotein monoclonal antibody was used because it can bind to non-linear/conformational epitopes of the N protein of SARS-CoV-2 and SARS-CoV. This protein can also induce innate memory in human primary monocytes.

Survey results

SARS-CoV-2 spike protein-specific antibodies were most reactive with the DTaP vaccine and, to a lesser extent, E. faecalis Bacteria are common human gut microbes.EBV antibodies against early antigen D (EBV-EAD), EBV-nuclear antigen (EBNA) and B. BurgdorferiBCG, measles, Escherichia coli CdT, EBV virus capsid antigen antibody (EBV-VCA), and varicella-zoster virus (VZV).

Milk, gliadin toxic peptides, pea protein, α+β casein, soybean, lentil lectin, and roasted almonds were found to react with SARS-CoV-2 spike protein antibodies. Furthermore, for SARS-CoV-2 nucleoprotein antibodies, the strongest reactions were seen with broccoli, soybean, pork, rice endochitinase, cashew, and gliadin toxic peptides.

Conclusion

The overall response between the SARS-CoV-2 nucleoprotein monoclonal antibody and the DTaP vaccine was found to be the strongest. In contrast, less robust responses were observed with other vaccines and common viral and bacterial antigens. E. faecalis and herpes virus. Surprisingly, no responses were observed to BCG vaccine antigens. Many food proteins and peptides have been found to share homology with the SARS-CoV-2 protein.

The results of the current study show that common viruses (e.g. herpes virus) and bacteria (e.g. Escherichia coli, Escherichia coli) protects against SARS-CoV-2 infection. Moreover, cross-reactivity between food antigens and different pathogens explains why most of the world’s population repeatedly exposed to different SARS-CoV-2 variants did not develop severe infections.