Antibodies against H1N1 influenza virus cross-react with α-cells of pancreatic islets

Abstract

Epidemiological studies have documented that the incidence of human type 1 diabetes was significantly increased after H1N1 epidemic. However, a direct link between human type 1 diabetes and virus infection remains elusive. We generated 84 clones of murine monoclonal antibodies against the H1N1, and carried out immunohistochemistry in normal human tissue microarray. The results showed that two clones specifically cross-reacted with human α-cells of pancreatic islets. Reverse transcription polymerase chain reaction and deoxyribonucleic acid sequencing showed that the amino acid sequences of light and heavy chains of these clones were different. Importantly, the expression profiles of two monoclonal antibodies were individual different. For the first time, we provide direct evidence that monoclonal antibodies against H1N1 can cross-react with human pancreas α-cells, another source of β-cells, suggesting α-cells might be a novel target to be investigated in diabetes research.

Keywords: Cross-reactivity; Monoclonal antibodies; Tissue microarrays.

Figure 1

Representative immunohistochemical images of two cross‐reactive antibodies in human pancreatic tissue microarrays. (a) From the staining pattern, H1‐17 and H1‐55 clones are stained with the surrounding cells of the pancreas islet. The sections were counterstained with hematoxylin (B‐4 is immunoglobulin G1 isotype antibody used as a negative staining control). (b) Positive numbers of immunohistochemical staining from 21 different pancreas tissues samples. Nearly 50% of samples were expressed in both H1‐17 and H1‐55 clones. (c) Immunohistochemical double staining of H1‐17 and H1‐55 (3,3′‐diaminobenzidine staining) with anti‐insulin (alkaline phosphatase‐red). Both antibodies are not localized in insulin‐secreting β‐cells. TMAs, tissue microarrays.

Figure 2

Representative images of double indirect immunofluorescence of two cross‐reactive antibodies with anti‐insulin and anti‐glucagon antibodies on human pancreatic tissues. (a) H1‐17 clone; (b) H1‐55 clone. Merged images showed that H1‐17 and H1‐55 antibodies were located in the glucagon‐secreting α‐cells (yellow signal), not β‐cells. FITC, fluorescein‐isothiocyanate.

Figure 3

(a) Immunohistological images of H1‐55 antibody with pancreatic tissues of other animals. Results showed that anti‐HA monoclonal antibodies H1‐55 cross‐reacted with the pancreatic tissues of rat, mouse and rabbit, but not with that of guinea pig. (b) Amino acid sequences of light and heavy chains of clones of H1‐17 and H1‐55. The results showed that the H1‐17 clones are different from that of H1‐55.