Near Complete Protection Against Covid-19 in a Section of Population: Implication of Lockdown on Development of Passive Vaccination to Counter SARS-CoV-2 Attack

COVID-19 is fast spreading around the globe in a highly contagious manner. Until date there are no therapeutic agents/vaccines developed which could control this highly infectious virus from spreading among human population. During early stage of COVID-19, stringent Lockdown was implemented throughout India on 25 March, 2020. Our earlier findings reflected that early introduction of complete Lockdown significantly controlled the spread of COVID-19 in the population immediately after Lockdown. It was hypothesized that immune response was responsible for the control of the spread of COVID-19. To further evaluate the role of immune response/passive vaccination, data from COVID-19 positive/recovered individuals in eight states were assessed for the month of December, 2020. The results from our study reflect that in all the eight states, there was marked decrease in the number of confirmed COVID-19 cases after Lockdown, with one region recording no COVID-19 cases. All the states studied had very low number of active cases; the minimum number being two even after such a long period from the start of this disease. A negative correlation between number of recovered individuals and number of active cases of COVID-19 was noted. Here we hypothesize that passive immunization may have played a significant role in controlling SARS-CoV-2. It could be inferred from this study that implementation of prolonged Lockdown was able attenuate the virus and create an environment for the development of passive immunity in the section of population studied.

Monoclonal IgM antibodies raised against Candida albicans Hyr1 provide cross-kingdom protection against Gram negative bacteria

Recent years have seen an unprecedented rise in the incidence of multidrug resistant (MDR) Gram negative bacteria (GNB) such as Acinetobacter and Klebsiella species. In view of the shortage of novel drugs in the pipeline, alternative strategies to prevent and treat infections by GNB are urgently needed. Previously, we have reported that the C. albicans hyphal-regulated protein Hyr1 shares striking 3D structural homology with cell surface proteins of A. baumannii; and active or passive vaccination with rHyr1p-N or anti-Hyr1p polyclonal antibody, respectively; protect mice from Acinetobacter infections. Here, we show that monoclonal antibodies (mAb) generated against Hyr1p, bind to the surface of Acinetobacter as well as K. pneumoniae. The anti-Hyr1 mAb also block damage to primary endothelial cells by the bacteria, and protect mice from lethal pulmonary infections mediated by A. baumannii and K. pneumoniae. Our current studies emphasize the potential of harnessing Hyr1p mAb as a cross-kingdom immunotherapeutic strategy against MDR GNB.

Immunooncology in Breast Cancer: Active and Passive Vaccination Strategies

Immunotherapies are set to become part of the therapeutic repertoire for breast cancer in the near future. Active vaccination is a promising strategy, especially in tumors that have a specific tumor-associated antigen. Although cellular immunotherapies have not yet shown efficacy, new technologies are on the way to improve this approach. Given the recent Food and Drug Administration approval of chimeric antigen receptor (CAR) T cells for leukemia, it is only a question of time before solid tumors will follow. However, not all breast cancer patients will respond to cellular or other immunotherapy. Hence, we must define subpopulations of breast cancer patients who benefit from this new approach.

Characterization and Epitope Mapping of the Polyclonal Antibody Repertoire Elicited by Ricin Holotoxin-Based Vaccination

ABSTRACTRicin, one of the most potent and lethal toxins known, is classified by the Centers for Disease Control and Prevention (CDC) as a select agent. Currently, there is no available antidote against ricin exposure, and the most promising therapy is based on neutralizing antibodies elicited by active vaccination or that are given passively. The aim of this study was to characterize the repertoire of anti-ricin antibodies generated in rabbits immunized with ricin toxoid. These anti-ricin antibodies exhibit an exceptionally high avidity (thiocyanate-based avidity index, 9 M) toward ricin and an apparent affinity of 1 nM. Utilizing a novel tissue culture-based assay that enables the determination of ricin activity within a short time period, we found that the anti-ricin antibodies also possess a very high neutralizing titer. In line with these findings, these antibodies conferred mice with full protection against pulmonary ricinosis when administered as a passive vaccination. Epitope mapping analysis using phage display random peptide libraries revealed that the polyclonal serum contains four immunodominant epitopes, three of which are located on the A subunit and one on the B subunit of ricin. Only two of the four epitopes were found to have a significant role in ricin neutralization. To the best of our knowledge, this is the first work that characterizes these immunological aspects of the polyclonal response to ricin holotoxin-based vaccination. These findings provide useful information and a possible strategy for the development and design of an improved ricin holotoxin-based vaccine.