Bacteria That Cause Enteric Diseases Stimulate Distinct Humoral Immune Responses

Abstract

Bacterial enteric pathogens individually and collectively represent a serious global health burden. Humoral immune responses following natural or experimentally-induced infections are broadly appreciated to contribute to pathogen clearance and prevention of disease recurrence. Herein, we have compared observations on humoral immune mechanisms following infection with Citrobacter rodentium, the model for enteropathogenic Escherichia coli, Vibrio cholerae, Shigella species, Salmonella enterica species, and Clostridioides difficile. A comparison of what is known about the humoral immune responses to these pathogens reveals considerable variance in specific features of humoral immunity including establishment of high affinity, IgG class-switched memory B cell and long-lived plasma cell compartments. This article suggests that such variance could be contributory to persistent and recurrent disease.

Know your enemy or find your friend?—Induction of IgA at mucosal surfaces

“…Thus, in mice that tolerate CT better than humans, a CT‐like response is a reasonable goal for mucosal vaccine response, both when it comes to levels of antibodies produced and types of cells induced. Similarly, certain mucosal infections give rise to long‐term protection after infection, while others do not 8,10 . To understand give long‐term protection, it is likely that CT will represent a relatively good model.…”

“…Similarly, certain mucosal infections give rise to long-term protection after infection, while others do not. 8 , 10 To understand give long-term protection, it is likely that CT will represent a relatively good model.…”

“…As pathogens may encounter IgA before they reach any tissues, IgA can potentially give rise to sterile immunity by hindering the initial infection 6 . Several studies of disease‐causing viruses, bacteria, toxins, or adjuvanted antigens applied at mucosal surfaces have demonstrated that antigen‐specific IgA responses are triggered against them 7‐10 . Airway viruses can also trigger antigen‐specific IgA responses, an example being the ongoing SARS‐CoV‐2 pandemic; in diseased individuals antigen‐specific IgA antibodies are often detected in serum before either IgM or IgG 11,12 .…”

“… 6 Several studies of disease-causing viruses, bacteria, toxins, or adjuvanted antigens applied at mucosal surfaces have demonstrated that antigen-specific IgA responses are triggered against them. 7 – 10 Airway viruses can also trigger antigen-specific IgA responses, an example being the ongoing SARS-CoV-2 pandemic; in diseased individuals antigen-specific IgA antibodies are often detected in serum before either IgM or IgG. 11 , 12 At the same time, IgA is often described as a non-inflammatory antibody class that hinders inflammation, and it has been suggested that a significant proportion of IgA is produced in a similar fashion as natural IgM in the absence of typical antigen activation.…”

Trivalent outer membrane vesicles-based combination vaccine candidate induces protective immunity against Campylobacter and invasive non-typhoidal Salmonella in adult mice

“…IL-17 is known to promote dendritic cell differentiation through upregulation of expression of cell-surface co-stimulatory molecules and induces Th-1 protective immune response against intracellular pathogens [72]. IFN-γ secreted by Th-1 cells mediates CD4 + splenic cell response, necessary for infection resistance and ultimate clearance of bacteria from tissues [73]. IL-6 contributes to bridge the gap between innate and adaptive immune responses.…”