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Emergence and Pathogenesis of Swine Influenza Viruses in Humans
Published in Sunit K. Singh, Human Respiratory Viral Infections, 2014
Jennifer L. Smith, Frederick T. Koster, Robert J. Hogan
In general, infection by influenza virus results in robust protection against homologous or highly similar viral strains based upon the HA and NA of the virus. Both long-lasting humoral and cell-mediated immunological memory are generated and maintained for long periods after resolution of the acute infection. This memory results in a rapid recall of both antibody and effector T cell immune responses to limit reinfection with homologous virus. It has long been accepted that virus-specific neutralizing antibodies of the IgA and IgG isotypes provide excellent protection from infection or severe disease. Likewise, they provide solid data with regard to correlates of immunity for influenza virus.143,144
Persistence of Passive Immunity, Natural Immunity (and Vaccination)
Published in Leonhard Held, Niel Hens, Philip O’Neill, Jacco Wallinga, Handbook of Infectious Disease Data Analysis, 2019
Amy K. Winter, C. Jessica E. Metcalf
The most direct source of data on susceptibility over age is serology, the study of, and testing for circulating antibodies against a pathogen using sera. With enzyme immunoassays (Figure 14.1b, one of many possible approaches for testing sera), sera can be tested for Immunoglobulin M (IgM), an antibody whose titers rise immediately after infection, but then quickly fall, thus making this antibody a good marker of recent infection; and Immunoglobulin G (IgG), an antibody whose titers rise, and then stay high for decades, after either infection or vaccination. Measles virus-specific, and rubella virus-specific IgG antibodies above a known threshold are recognized correlates of immunity [11, 12] whether resulting from the transfer of maternal antibodies, natural infection, or vaccination (Figure 14.1c). Age-specific IgG serology thus can inform directly patterns of immunity (and in turn susceptibility) over age, and their complex fluctuations. In this chapter, we focus on IgG serology, and consider approaches for interpreting serological profiles over age commonly available from cross-sectional studies. We first broadly introduce the age profile of immunity for immunizing infections, and its determinants and discuss the basic tool-set for inference around this type of data, introducing methods for both continuous and binary response variables, indicating how this can reveal the underlying dynamical drivers. We conclude with a case study on use of IgG serology for rubella across the spectrum from endemic to elimination settings and outline some directions for further statistical and methodological innovation.
Multi-functional antibody profiling for malaria vaccine development and evaluation
Published in Expert Review of Vaccines, 2021
D. Herbert Opi, Liriye Kurtovic, Jo-Anne Chan, Jessica L. Horton, Gaoqian Feng, James G. Beeson
Although there are currently no well-established correlates of immunity, several assays are valuable for assessing candidate vaccines in pre-clinical development and clinical trials until clear immunological correlates are defined. Measurements of IgG magnitude alone, while commonly performed, have not reliably correlated with protection or vaccine efficacy with increasing evidence supporting a greater need for assays of antibody function. The breadth of functional activities of antibodies involved in mediating immunity to malaria, and the lack of consistent associations between current reference assays and vaccine efficacy suggest that evaluation of vaccine-induced immunity should include quantifying multiple-antibody functions. These include direct inhibitory or neutralizing activity, interactions with complement factors, and Fcγ-receptor mediated functions, as well as some other specific assays. Currently, there are few established reference assays for assessing vaccine-induced functional antibodies, but these are mostly applied individually and therefore do not reflect the full range of functional anti-malarial antibody responses induced by vaccines. Additionally, due to technical limitations a number of these assays are not amenable to high throughput platforms and therefore not easy to apply in large vaccine trials.
An overview of human leptospirosis vaccine design and future perspectives
Published in Expert Opinion on Drug Discovery, 2020
Carolina R. Felix, Bianca S. Siedler, Liana N. Barbosa, Gabriana R. Timm, Johnjoe McFadden, Alan J. A. McBride
The development of a universal vaccine against leptospirosis is only likely to be achieved through the recombinant vaccine route, and although we appear to be no closer than we were 20 years ago, there are encouraging results that show the field is making progress. Several hundred novel vaccine candidates have been identified using in silico approaches combined with the novel application of experimental confirmation of the surface-exposure of these proteins. However, progress is inhibited by the lack of correlates of immunity and absence of a consensus on the protocols used to evaluate vaccine candidates in a suitable animal model. This has made it difficult to interpret the published data and overcome the hurdles toward moving potential vaccine candidates into pre-clinical and clinical trials. We propose that establishment of a standardized protocol for the evaluation of efficacy of recombinant vaccines be a priority for the field that would enable it to overcome these shortcomings.
The effect of the third dose of the BNT162b2 vaccine on anti-SARS-CoV-2 spike antibody levels in healthcare workers with and without COVID-19 infection
Published in Annals of Medicine, 2023
Blanka Wolszczak-Biedrzycka, Anna Bieńkowska, Beata Cieślikiewicz, Elwira Smolińska-Fijołek, Grzegorz Biedrzycki, Justyna Dorf
Vaccines against COVID-19 have immense potential to confer long-lasting humoral immunity. However, further research is needed to define the correlates of immunity and protective titers to determine the need for the third and successive booster doses. The protection conferred by the booster dose should be analyzed in the context of global vaccine shortages to identify the most susceptible populations without compromising the global vaccination campaign against COVID-19.