Generation of Neutralizing Human Monoclonal Antibodies against Parvovirus B19 Proteins

Abstract

Infections caused by human parvovirus B19 are known to be controlled mainly by neutralizing antibodies. To analyze the immune reaction against parvovirus B19 proteins, four cell lines secreting human immunoglobulin G monoclonal antibodies (MAbs) were generated from two healthy donors and one human immunodeficiency virus type 1-seropositive individual with high serum titers against parvovirus. One MAb is specific for nonstructural protein NS1 (MAb 1424), two MAbs are specific for the unique region of minor capsid protein VP1 (MAbs 1418-1 and 1418-16), and one MAb is directed to major capsid protein VP2 (MAb 860-55D). Two MAbs, 1418-1 and 1418-16, which were generated from the same individual have identity in the cDNA sequences encoding the variable domains, with the exception of four base pairs resulting in only one amino acid change in the light chain. The NS1- and VP1-specific MAbs interact with linear epitopes, whereas the recognized epitope in VP2 is conformational. The MAbs specific for the structural proteins display strong virus-neutralizing activity. The VP1- and VP2-specific MAbs have the capacity to neutralize 50% of infectious parvovirus B19 in vitro at 0.08 and 0.73 μg/ml, respectively, demonstrating the importance of such antibodies in the clearance of B19 viremia. The NS1-specific MAb mediated weak neutralizing activity and required 47.7 μg/ml for 50% neutralization. The human MAbs with potent neutralizing activity could be used for immunotherapy of chronically B19 virus-infected individuals and acutely infected pregnant women. Furthermore, the knowledge gained regarding epitopes which induce strongly neutralizing antibodies may be important for vaccine development.

Parvovirus B19 infection in human pregnancy

“…201 Unlike varicella zoster Ig administration for VZV infection, maternal IgG administration, fetal hPV B19 IgG-rich high-titre c-globulin therapy and human monoclonal IgG antibody therapy have limited efficacy in the management of hPV B19 infection in pregnancy, and further evaluation is necessary. [202][203][204][205] In one pregnant woman infected with hPV B19, high-dose intravenous c-globulin was used in placental exchange transfusion, 202 and IgG monoclonal antibodies with potent neutralising activity have been generated from individuals with high serum titres against hPV B19. It is possible that these antibodies may provide immunotherapy in those chronically infected or in pregnant women with acute infection.…”

“…It is possible that these antibodies may provide immunotherapy in those chronically infected or in pregnant women with acute infection. 204…”

Characterization of antibodies that inhibit HIV gp120 antigen processing and presentation

“…mAb 39H10/A11 and 87E4/ A8 (both IgG2j) were generated from a gp120-immunized Xeno Mouse G2 strain; mAb 39H10/A11 recognizes an undefined conformational gp120 epitope that was distinct from the CD4-binding site or the chemokine receptor-binding site (designated Conf B) [13], while mAb 87E4/A8 does not recognize gp120 IIIB and was included in some experiments as a negative control. mAb specific for human parvovirus B19 [860-55D (IgG1k) or 1418 (IgG1j)] were also used as irrelevant mAb control [31]. All mAb were purified using protein A or protein G columns (Amersham Pharmacia Biotech, Piscataway, NJ).…”

Circulating cytokines and chemokines in acute symptomatic parvovirus B19 infection: Negative association between levels of pro‐inflammatory cytokines and development of B19‐associated arthritis

“…Autoantibody production is increasingly recognised in association with B19 infection [Loizou et al, 1997;Lunardi et al, 1998]. Both humoral and cell-mediated immunity have been demonstrated against VP1/2 antigens in persons with past B19 infection [Von Poblotzki et al, 1996;Gigler et al, 1999] and the progression of these responses in this [Wagner et al, 1995;Franssila et al, 2001] and other virus infections may be mediated by the type of CD4þ T-cell response [Goodbourn et al, 2000;Hunter and Reiner, 2000].…”