An automated approach to determine antibody endpoint titers for COVID-19 by an enzyme-linked immunosorbent assay

While a variety of therapeutic options continue to emerge for COVID-19 treatment, convalescent plasma (CP) has been used as a possible treatment option early in the pandemic. One of the most significant challenges with CP therapy, however, both when defining its efficacy and implementing its approach clinically, is accurately and efficiently characterizing an otherwise heterogenous therapeutic treatment. Given current limitations, our goal is to leverage a SARS antibody testing platform with a newly developed automated endpoint titer analysis program to rapidly define SARS-CoV-2 antibody levels in CP donors and hospitalized patients. A newly developed antibody detection platform was used to perform a serial dilution enzyme-linked immunosorbent assay (ELISA) for immunoglobulin (Ig)G, IgM, and IgA SARS-CoV-2 antibodies. Data were then analyzed using commercially available software, GraphPad Prism, or a newly developed program developed in Python called TiterScape, to analyze endpoint titers. Endpoint titer calculations and analysis times were then compared between the two analysis approaches. Serial dilution analysis of SARS-CoV-2 antibody levels revealed a high level of heterogeneity between individuals. Commercial platform analysis required significant time for manual data input and extrapolated endpoint titer values when the last serial dilution was above the endpoint cutoff, occasionally producing erroneously high results. By contrast, TiterScape processed 1008 samples for endpoint titer results in roughly 14 minutes compared with the 8 hours required for the commercial software program analysis. Equally important, results generated by TiterScape and Prism were highly similar, with differences averaging 1.26 ± 0.2 percent (mean ± SD). The pandemic has created unprecedented challenges when seeking to accurately test large numbers of individuals for SARS-CoV-2 antibody levels with a rapid turnaround time. ELISA platforms capable of serial dilution analysis coupled with a highly flexible software interface may provide a useful tool when seeking to define endpoint titers in a high-throughput manner. Immunohematology 2021;37:33-43. While a variety of therapeutic options continue to emerge for COVID-19 treatment, convalescent plasma (CP) has been used as a possible treatment option early in the pandemic. One of the most significant challenges with CP therapy, however, both when defining its efficacy and implementing its approach clinically, is accurately and efficiently characterizing an otherwise heterogenous therapeutic treatment. Given current limitations, our goal is to leverage a SARS antibody testing platform with a newly developed automated endpoint titer analysis program to rapidly define SARS-CoV-2 antibody levels in CP donors and hospitalized patients. A newly developed antibody detection platform was used to perform a serial dilution enzyme-linked immunosorbent assay (ELISA) for immunoglobulin (Ig)G, IgM, and IgA SARS-CoV-2 antibodies. Data were then analyzed using commercially available software, GraphPad Prism, or a newly developed program developed in Python called TiterScape, to analyze endpoint titers. Endpoint titer calculations and analysis times were then compared between the two analysis approaches. Serial dilution analysis of SARS-CoV-2 antibody levels revealed a high level of heterogeneity between individuals. Commercial platform analysis required significant time for manual data input and extrapolated endpoint titer values when the last serial dilution was above the endpoint cutoff, occasionally producing erroneously high results. By contrast, TiterScape processed 1008 samples for endpoint titer results in roughly 14 minutes compared with the 8 hours required for the commercial software program analysis. Equally important, results generated by TiterScape and Prism were highly similar, with differences averaging 1.26 ± 0.2 percent (mean ± SD). The pandemic has created unprecedented challenges when seeking to accurately test large numbers of individuals for SARS-CoV-2 antibody levels with a rapid turnaround time. ELISA platforms capable of serial dilution analysis coupled with a highly flexible software interface may provide a useful tool when seeking to define endpoint titers in a high-throughput manner. Immunohematology 2021;37:33–43.

Interaction of bacteria and bacterial toxins with intestinal epithelial cells

The epithelium of the intestinal tract is a key barrier between the external environment and the internal body environment. Intestinal epithelial cells are targets for luminal bacteria and viruses and must discriminate between pathogenic and nonpathogenic commensal organisms. Pathogenic bacteria and their secreted products influence epithelial cell function and induce diarrhea by numerous mechanisms that range from an effect on epithelial cell-cell associations to intracellular signal transduction pathways. These effects lead to an inflammatory response and an influx of neutrophils into the epithelium. Infiltrating neutrophils, in turn, signal to epithelial cells, induce a secretory response, and perpetuate the diarrhea. Conversely, commensal bacteria have the ability to suppress inflammatory responses by inhibiting specific intracellular signal transduction pathways. Some of these diverse host pathogenic responses are addressed in this review.

Homeobox genes and congenital malformations

In this review we have built a case for abnormal Hox gene expression in human congenital malformations without presenting any direct evidence of their involvement. This approach is justified by the dramatic advances in developmental genetics which emphasize the considerable similarity in the primary processes and molecules used to guide early morphogenesis in all species. Hox genes occupy a central role in this scheme, being activated in a specific rostral-caudal order after initial specification of the basic embryonic axes and, thereafter, specifying positional identity by influencing downstream "realizator" genes that carry out the position-specific program. These theoretical arguments, together with the dramatic results obtained in an evolutionarily similar organism (the mouse) using the transgenic and gene deletion approaches, make it highly likely that abnormalities in Hox gene structure and expression will soon be implicated in specific human congenital malformation syndromes. In parallel with this phenotypic analysis, we can expect that the animal models discussed in this review will provide greater detail regarding the upstream regulators and downstream targets of Hox gene products. Together these approaches promise to finally elucidate some of the underlying mechanisms responsible for human congenital malformations.

Neuroendocrine carcinoma in a patient with hairy cell leukemia: a case report

Second malignancies are common in hairy cell leukemia. We report a case of a neuroendocrine carcinoma arising in a patient who had been diagnosed with hairy cell leukemia 6 years earlier. This case is the first report of these two tumors' occurring together. The pathogenetic basis for the presence of these two uncommon tumors in our patient is discussed.

Vaxstrate: an anti-reproductive vaccine for cattle

This paper describes the development of a vaccine for the prevention of pregnancy in female cattle. The vaccine is based on the established principle that antibodies to the hypothalamic releasing hormone, gonadotrophin releasing hormone (GnRH) block the action of GnRH on pituitary secretion of luteinizing hormone and follicle stimulating hormone, leading to gonadal atrophy in mammals. The vaccine comprises an immunogenic GnRH:ovalbumin conjugate formulated in a novel double adjuvant system and is administered in a two-dose treatment regimen. Field trials have confirmed efficacy and the product, Vaxstrate, has now been registered and commercialized.