Search

Nontypeable Haemophilus influenzae (NTHi) has emerged as a dominant mucosal pathogen causing acute otitis media (AOM) in children, acute sinusitis in children and adults, and acute exacerbations of chronic bronchitis in adults. Consequently, there is an urgent need to develop a vaccine to protect against NTHi infection. A multi‐component vaccine will be desirable to avoid emergence of strains expressing modified proteins allowing vaccine escape. Protein D (PD), outer membrane protein (OMP) 26, and Protein 6 (P6) are leading protein vaccine candidates against NTHi. In pre‐clinical research using mouse models, we found that recombinantly expressed PD, OMP26, and P6 induce robust antibody responses after vaccination as individual vaccines, but when PD and OMP26 were combined into a single vaccine formulation, PD antibody levels were significantly lower. We postulated that PD and OMP26 physiochemically interacted to mask PD antigenic epitopes resulting in the observed effect on antibody response. However, column chromatography and mass spectrometry analysis did not support our hypothesis. We postulated that the effect might be in vivo through the mechanism of protein vaccine immunologic antigenic competition. We found when PD and OMP26 were injected into the same leg or separate legs of mice, so that antigens were immunologically processed at the same or different regional lymph nodes, respectively, antibody levels to PD were significantly lower with same leg vaccination. Different leg vaccination produced PD antibody levels quantitatively similar to vaccination with PD alone. We conclude that mixing PD and OMP26 into a single vaccine formulation requires further formulation studies. [ABSTRACT FROM AUTHOR]

Respiratory syncytial (RSV) and parainfluenza (PIV) viruses are primary causes of acute bronchiolitis and wheezing illnesses in infants and young children. To further understand inflammation in the airways following infection, we tested for the presence of matrix metalloproteinases (MMP) and natural tissue inhibitors of MMP (TIMP) in primary and established human cell lines, and in the nasopharyngeal secretions (NPS) of human infants infected with RSV or PIV. Using ELISA and multiplex‐based assays, MMP‐9 and TIMP‐1 proteins were, respectively, detected in 66/67 and 67/67 NPS. During PIV or RSV infection TIMP‐1 concentrations were associated with hypoxic bronchiolitis. TIMP‐1 amounts were also negatively correlated with O2 saturation, and positively correlated with IL‐6, MIP‐1α, and G‐CSF amounts following RSV infection. IL‐6, MIP‐1α, and G‐CSF were negatively correlated with O2 saturation during RSV infection. Acute respiratory tract disease was not associated with MMP‐9 protein/protease activity. Additional studies using real‐time quantitative PCR suggested that MMP‐9 mRNA copy numbers were elevated in normal human bronchial epithelial (NHBE) cells infected with RSV, while TIMP‐1 and TIMP‐2 were not increased. However, ELISA did not reveal MMP‐9 protein in the NHBE cell culture supernatants. Hence, the data implied that airway epithelial cells were not the primary source of MMP or TIMP following paramyxovirus infection. Taken together, the data suggested that paramyxovirus infection perturbs MMP‐9/TIMP‐1 homeostasis that in turn may contribute to the severity of respiratory tract disease. J. Med. Virol. 79:447–456, 2007. © 2007 Wiley‐Liss, Inc. [ABSTRACT FROM AUTHOR]

A history of acute bronchiolitis in infancy caused by respiratory syncytial virus is a risk factor for recurrent wheezing in early childhood. Because the attachment (G) protein sensitizes mice for pulmonary eosinophilia and because Th2 cells are central in the pathogenesis of asthma, plasma and peripheral blood mononuclear cells (PBMC) from donors with asthma and from healthy donors were evaluated for anti--G protein responses. A significant trend con-necting severity of asthma with anti--G protein IgG1 and IgG2 titers was observed. The cor-relation between anti--F protein IgG3 titers and asthmaseverity approached significance. Peptide mapping studies revealed that more positive recall responses (interferon-gamma and interleukin-10 secretion) occurred after PBMC from donors with asthma were stimulated with peptides representing the nonglycosylated domain of G protein. The same peptides elicited more positive recall responses (proliferation and interferon-gamma secretion) in the PBMC of healthy donors. These data suggest that a mechanism may exist whereby adaptive immune responses against G protein contribute to wheezing. [ABSTRACT FROM AUTHOR]