This issue of the International Reviews of Immunology is dedicated to the interface between microbes and immunity, and its translational and therapeutic implications.
Fong et al. discuss in detail the interaction between probiotic bacteria and local, as well as systemic, immunity. Probiotics have profound effects on immunity through maintaining its tonicity and regulating T helper responses. For example, certain strains of Lactobacillus suppress allergies during the ontogenesis of the immune system. The authors present evidence supporting the mechanism associated with the interaction between microbes and immunity: probiotic bacterial cells and their soluble factors activate locally dendritic cells and monocytes/macrophages via toll-like-receptors. These, in turn, regulate the activity of the adaptive immunity, especially that of T cells.
In a review on a complementary topic, Gnauck et al. review the characteristics and function of bacterial lipopolysaccharides and their toxic potential in humans. As the cross-talk between enteral microbiota and human host is essential for the development and maintenance of the human gastrointestinal and systemic immune system, Gram-negative bacteria in the gut lumen are thought to promote the development of a balanced gut immune response. Nevertheless, the entry of Gram-negative bacteria-derived LPS into systemic circulation may lead to a deleterious pro-inflammatory systemic immune response. For example, recent data suggest that chronically low levels of circulating LPS may be associated with the development of metabolic conditions such as insulin resistance, type 2 diabetes, atherosclerosis and cardiovascular disease. The authors discuss, in detail, key aspects related to the interaction between LPS and immunity, with therapeutic implications.
In an opinion paper, Zakeri et al. reviewed recent literature on the interplay between helminths, TLRs and asthma. Since TLRs orchestrate innate and adaptive immune response, their manipulation has been widely considered as a potential approach to control asthma symptoms. It is well established that helminths have immunoregulatory effects on host immune responses, especially innate immunity. Based on preclinical studies, harnessing helminth-derived molecules affecting TLRs can be considered as a potential biological therapy for allergic diseases including asthma.
There are still substantial controversies regarding approaches to blocking mother-to-child transmission of Hepatitis B. This remains a serious worldwide social and public health problem. Approximately 35–50% of HBV carriers are infected through vertical transmission. Even after newborn immunoprophylaxis, vertical transmission still accounts for 5–10% of HBV carriers in China. For this reason, it is important to determine how to effectively intervene in mother-to-child transmission (MTCT). Ren et al. discuss this subject and propose several directions towards effective control of MTCT for Hepatitis B virus, which remains a key objective for the future.
At last but not least, D'Amelio et al. review anti-infectious human vaccination from a historical perspective. The authors present a brief history of vaccination since Jenner's work, through the first golden age of vaccinology (from Pasteur's era to 1938), the second golden age (from 1940 to 1970) and the current period dominated by molecular biology and recombinant vaccines. In the first golden age, live vaccines such as Bacille Calmette Guérin (BCG) and yellow fever, as well as inactivated vaccines, such as typhoid, cholera, plague and influenza, were developed. In the second golden age the cell culture technology enabled polio, measles, mumps and rubella vaccine development. In the era of modern vaccines, in addition to the conjugate polysaccharide, hepatitis A, oral typhoid and varicella vaccines, the advent of molecular biology enabled the development of hepatitis B, acellular pertussis, papillomavirus and rotavirus recombinant vaccines. The authors discuss the extraordinary impact of vaccines on human health throughout history and articulate some of the key questions and goals for the future.