SARS-CoV-2: The Self-Nonself Issue and Diagnostic Tests

Abstract

Objective At present, false negatives/positives have been reported in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics. Searching for the molecular basis of such tests' unreliability, this study aimed at defining how specific are the sequences used in serological and polymerase chain reaction (PCR) tests to detect SARS-CoV-2. Materials and Methods Analyses were performed on the leading SARS-CoV-2 biomarker spike glycoprotein (gp). Sharing of peptide sequences between the spike antigen and the human host was analyzed using the Peptide Search program from Uniprot database. Sharing of oligonucleotide sequences was investigated using the nucleotide Basic Local Alignment Search Tool (BLASTn) from National Center for Biotechnology Information (NCBI). Results Two main points stand out: (1) a massive pentapeptide sharing exists between the spike gp and the human proteome, and only a limited number of pentapeptides (namely 107) identify SARS-CoV-2 spike gp as nonself when compared with the human proteome, and (2) the small phenetic difference practically disappears at the genetic level. Indeed, almost all of the 107 pentadecameric nucleotide sequences coding for the pentapeptides unique to SARS-CoV-2 spike gp are present in human nucleic acids too. Conclusions The data are of immunological significance for defining the issue of the viral versus human specificity and likely explain the fact that false positives can occur in serological and PCR tests for SARS-CoV-2 detection.

Maiden Impact Factor to Journal of Laboratory Physicians: An Encouragement for Editors and Authors

“…These articles were written on important and timely issues of biomedical waste management during the COVID-19 epidemic, 14 and pathological findings in the autopsies done on COVID-19 victims. 15 Articles published in 2023 on COVID-19 include an original paper from Italy, 16 which describes selective index of various molecular and serological tests being used on the human clinical samples for the diagnosis of severe acute respiratory syndrome coronavirus 2 and the specificity can be compromised of these tests if care is not taken during their development. Two other papers describe emergence of new opportunistic bacterial and fungal infection in the era of COVID-19 and how these infections complicated the outcome of these patients.…”