Detection of Cytomegalovirus Interleukin 10 (cmvIL-10) by Enzyme-Linked Immunosorbent Assay (ELISA).

Since its introduction in 1971, the enzyme-linked immunosorbent assay (ELISA) has revolutionized medicine by enabling detection of both antigens and antibodies in a variety of samples. We describe here a customized sandwich ELISA developed for the detection of Human Cytomegalovirus interleukin-10 (cmvIL-10). CmvIL-10 is a virally encoded cytokine and ortholog of human interleukin 10 (hIL-10). While cmvIL-10 and hIL-10 are similar in structure and function, overall amino acid sequence identity is only 27%, resulting in antigenically distinct proteins. The cmvIL-10 ELISA is specific and does not detect hIL-10. The assay is sensitive enough to detect cmvIL-10 in both culture supernatants and patient serum. The ability to quantify cmvIL-10 levels during HCMV infection could provide valuable information about immune evasion strategies and viral control of host signaling pathways.

Modulation of the Host Environment by Human Cytomegalovirus with Viral Interleukin 10 in Peripheral Blood.

Background: Human cytomegalovirus (HCMV) is a herpesvirus with both lytic and latent life cycles. Human cytomegalovirus encodes 2 viral cytokines that are orthologs of human cellular interleukin 10 (cIL-10). Both cytomegalovirus interleukin 10 (cmvIL-10) and Latency-associated cytomegalovirus interleukin 10 (LAcmvIL-10) (collectively vIL-10) are expressed during lytic infection and cause immunosuppressive effects that impede virus clearance. LAcmvIL-10 is also expressed during latent infection of myeloid progenitor cells and monocytes and facilitates persistence. Here, we investigated whether vIL-10 could be detected during natural infection. Methods: Plasma from healthy blood donors was tested by enzyme-linked immunosorbent assay for anti-HCMV immunoglobulin G and immunoglobulin M and for cIL-10 and vIL-10 levels using a novel vIL-10 assay that detects cmvIL-10 and LAcmvIL-10, with no cross-reactivity to cIL-10. Results: vIL-10 was evident in HCMV+ donors (n = 19 of 26), at levels ranging 31-547 pg/mL. By comparison, cIL-10 was detected at lower levels ranging 3-69 pg/mL. There was a strong correlation between vIL-10 and cIL-10 levels (P = .01). Antibodies against vIL-10 were also detected and neutralized vIL-10 activity. Conclusions: vIL-10 was detected in peripheral blood of healthy blood donors. These findings suggest that vIL-10 may play a key role in sensing or modifying the host environment during latency and, therefore, may be a potential target for intervention strategies.