Functional differences between antiviral activities of sulfonated and intact intravenous immunoglobulin preparations toward varicella-zoster virus and cytomegalovirus

Polyvalent human immunoglobulin for infectious diseases: Potential to circumvent antimicrobial resistance

Antimicrobial resistance (AMR) is a global health problem that causes more than 1.27 million deaths annually; therefore, it is urgent to focus efforts on solving or reducing this problem. The major causes of AMR are the misuse of antibiotics and antimicrobials in agriculture, veterinary medicine, and human medicine, which favors the selection of drug-resistant microbes. One of the strategies proposed to overcome the problem of AMR is to use polyvalent human immunoglobulin or IVIG. The main advantage of this classic form of passive immunization is its capacity to enhance natural immunity mechanisms to eliminate bacteria, viruses, or fungi safely and physiologically. Experimental data suggest that, for some infections, local administration of IVIG may produce better results with a lower dose than intravenous application. This review presents evidence supporting the use of polyvalent human immunoglobulin in AMR, and the potential and challenges associated with its proposed usage.

Everolimus delayed and suppressed cytomegalovirus DNA synthesis, spread of the infection, and alleviated cytomegalovirus infection

Everolimus is an inhibitor of mammalian target of rapamycin (mTOR) and reduces the risk of cytomegalovirus (CMV) infection in transplant recipients. Everolimus inhibits mTOR complex 1, which regulates factors involved in several crucial cellular functions and is required for CMV replication. However, it is not clear how everolimus regulates CMV replication and prevents and alleviates CMV infection. Effects of everolimus on CMV infection, spread, and DNA synthesis and release from infected cells were assessed by plaque formation, infectious centre assay, real-time PCR of infected cells, and culture supernatant in CMV-infected cultures with and without everolimus. Everolimus enhanced plaque formation by 3.6 times, but the size of the plaques was reduced to 36.4% of untreated cultures in the absence of a pretreatment period. Everolimus reduced viral adsorption but enhanced the replication efficiency of inoculated virus, resulting in an increase in plaque number in the early phase of infection. Preinfection treatment of cells with everolimus efficiently exhibited its antiviral efficacy, and everolimus delayed and suppressed viral DNA synthesis and release from infected cells. Everolimus had suppressed the spread of infection and reduced the number of total infected cells to 40% of untreated cells on day 9, indicating reduction of the size of CMV lesions to one-sixth in 2-3 replication cycles. Preinfection treatment of the cells with everolimus augmented its suppressive effect on CMV infection and replication. Everolimus reduced the total number of infected cells and limited the CMV lesions, and this reduction in the spread of CMV infection would alleviate CMV infection in transplant recipients.

Interaction of Immunoglobulin with Cytomegalovirus-Infected Cells

Intravenous immunoglobulin (IVIG) is used to treat or prevent severe viral infection, especially cytomegalovirus (CMV) infections. IVIG was characterized to understand its interaction with CMV-infected cells. IVIG retarded CMV spread and reduced virus yields depending on the neutralizing (NT) antibody titer. Immediate early protein synthesis was reduced by IVIG in 3 to 15 h, and IVIG specifically reduced the ratio of 66/68k protein synthesis among immediate early proteins in an NT antibody-dependent manner between 4 and 8 h after infection, indicating that antigenic modulation of CMV-infected cells by IVIG reduced viral protein synthesis and virus production. The half-life of antibody bound to CMV-infected cells was 3.8 h. NT antibody titers to varicella-zoster virus (VZV) and CMV in IVIG were dose dependently absorbed by cells infected with VZV and CMV, respectively, but the antibody titers to CMV and VZV, respectively, were not affected. NT antibody in 0.3 mL of IVIG (15 mg) was specifically absorbed by 10⁸ CMV-infected cells and 10⁷ VZV-infected cells, suggesting that the NT antibody in IVIG might be inactivated by one-tenth of a similar volume of CMV-infected or VZV-infected cells. Various antiviral activities of IVIG may contribute to control and alleviation of CMV infection.