Identification of antigens recognized by salivary IgA using microbial protein microarrays

Abstract

Secretory IgA plays an important role in the mucosal immune system for protection against pathogens. However, the antigens recognized by these antibodies have only been partially studied. We comprehensively investigated the antigens bound by salivary IgA in healthy adults using microbial protein microarrays. This confirmed that saliva contained IgA antibodies that bind to a variety of pathogenic microorganisms, including spike proteins of severe acute respiratory syndrome coronavirus 2, severe acute respiratory syndrome coronavirus, Middle East respiratory syndrome coronavirus, and other human coronavirus species. Also, many subtypes and strains of influenza virus were bound, regardless of the seasonal or vaccine strains. Salivary IgA also bound many serogroups and serovars of Escherichia coli and Salmonella . Taken together, these findings suggest that salivary IgA, which exhibits broad reactivity, is likely an essential element of the mucosal immune system at the forefront of defense against infection.

Lactobacillus paragasseri SBT2055 Activates Plasmacytoid Dendritic Cells and Improves Subjective Symptoms of Common Cold in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Parallel-Group Comparative Trial

“…In this study, the secretion rate of salivary sIgA was used to select immune-weakened participants. Salivary sIgA is known to bind to various pathogenic organisms and prevent host infections [32]. The salivary sIgA secretion level may reflect the immune function in the oral cavity and upper respiratory tract.…”

Oral Microbiota: The Influences and Interactions of Saliva, IgA, and Dietary Factors in Health and Disease

“…Notably, sIgA produced by the oral mucosa and salivary glands binds to viruses and resident bacteria that invade the oral cavity, thereby blocking their adherence to the oral mucosa [ 83 ]. Recent reports indicate that sIgA can bind not only to viruses and bacteria that have been previously encountered but also to those that have not yet caused infection [ 84 ]. Consequently, oral sIgA might play an essential role in defending against infections caused by novel pathogens such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2).…”

Antibody Profiling of Microbial Antigens in the Blood of COVID-19 mRNA Vaccine Recipients Using Microbial Protein Microarrays

“…Fukushima Medical University has developed a protein microarray carrying protein extracts and antigenic proteins from more than 4000 human-related microorganisms [21]. Using this microbial microarray, it is possible to profile antibodies against microorganisms present in the human blood.…”

“…Using this microbial microarray, it is possible to profile antibodies against microorganisms present in the human blood. Microbial protein microarrays were utilized to profile serum IgG, comprising 3437 protein extract samples and 1606 recombinant protein samples from an array of pathogens such as viruses, bacteria, and fungi, among others, sourced from the Fukushima Translational Research Project, Fukushima, Japan [21]. Briefly, during post-blocking, the microarrays were treated with diluted saliva samples along with Goat Reference Antibody Mix I (procured from Fukushima Protein Factory, Inc., Fukushima, Japan) and then stained with Alexa Fluor 647-labeled anti-human IgA and Cy3-labeled anti-goat IgG antibodies.…”