Carrier Properties of a Protein Derived from Outer Membrane Protein A ofKlebsiella pneumoniae

Abstract

We have recently cloned a new protein, recombinant P40 (rP40). When tested in vivo after conjugation to a B-cell epitope, rP40 induces an important antibody response without the need for adjuvant. To characterize its potency, this carrier protein was coupled to a peptide derived from respiratory syncytial virus attachment G protein (G1′). After immunization of mice with the rP40-G1′ conjugate, strong antipeptide antibodies were detected, whereas peptide alone was not immunogenic. To emphasize the carrier properties of rP40, a polysaccharide derived from Haemophilus influenzae type b (Hib) was coupled to it. Immunoglobulin G responses against the Hib polysaccharide were observed after coupling to rP40. Interestingly, an antipeptide antibody response was observed despite preexisting anti-rP40 antibodies generated by preimmunization with rP40. In addition, rP40 compares well with the reference carrier protein, tetanus toxoid (TT), since antibody responses of equal intensity were observed when a peptide or a polysaccharide was coupled to TT and rP40. Moreover, rP40 had advantages compared to TT; e.g., it induced a mixed Th1/Th2 response, whereas TT induced only a Th2 profile. Together, the results indicate that rP40 is a novel carrier protein with potential for use as an alternative carrier for human vaccination.

Differential Effects of Parainfluenza Virus Type 3 on Human Monocytes and Dendritic Cells

“…The binding of the anti-CD83 mAb (Immunotech, Marseille, France) was revealed by FITClabeled anti-mouse IgG Ab (Silenus, Hauworth, Australia). Expression of viral antigens on the cell surface was determined by incubation with polyclonal immune sera (1/200) obtained from BALB/c mice (purchased from IFFA CREDO, l'Arbresle, France) immunized by 3 ip injections either with 100 l of purified PIV3 with complete Freund adjuvant (50% v/v, Sigma) or, for the control mouse antiserum, with 20 g of P40, which is the outer membrane protein A (OMPA) of Klebsiella pneumoniae (Rauly et al, 1999). FITC-labeled anti-mouse IgG Ab was used as a secondary reagent.…”

Outer membrane protein A renders dendritic cells and macrophages responsive to CCL21 and triggers dendritic cell migration to secondary lymphoid organs

“…LN after injection of KpOmpA-treated DC (150±30×10 3 fluorescent cells/LN compared to 8±2×10 3 with BSA-treated DC; mean ± SD, n=3). In contrast, using macrophages treated for 8, 24 and 48 h with KpOmpA or LPS, we failed in detecting fluorescent cells in the draining LN, at any time point analyzed (8,16 or 48 h) (data not shown). These data show that KpOmpA activates DC and allows them to migrate from the periphery to the LN.…”

“…Even though soluble foreign proteins are usually poorly immunogenic in the absence of adjuvant [3], OmpA from different species induce specific humoral [4][5][6] and cytotoxic responses [7]. OmpA has, therefore, been proposed to design anti-infectious and anti-tumor vaccines [4,[7][8][9]. Among them, the recombinant OmpA from Klebsiella pneumoniae (KpOmpA) has carrier properties [8] and initiates protective cytotoxic responses specific for tumor antigens [9].…”

“…OmpA has, therefore, been proposed to design anti-infectious and anti-tumor vaccines [4,[7][8][9]. Among them, the recombinant OmpA from Klebsiella pneumoniae (KpOmpA) has carrier properties [8] and initiates protective cytotoxic responses specific for tumor antigens [9]. Recent data show that human and murine APC recognize KpOmpA via specific cell surface receptor(s) [9][10][11].…”

β-Barrel outer membrane proteins suppress mTORC2 activation and induce autophagic responses

“…Mitochondrial, chloroplast, and bacterial OMPs share a structural fold, the -barrel, because these eukaryotic organelles are evolutionarily derived from endosymbiotic bacteria. Bacterial OMPs from different species induce specific mammalian responses (1)(2)(3), which may explain their utility as components of vaccines, independently of their specific antigenicity or ability to be targets for cytotoxic antibodies that fix complement (2,4). OMPs can induce inflammatory cytokine secretion by macrophages (5), trigger costimulatory molecule expression on dendritic cells (6), and induce phagocyte migration to secondary lymphoid organs (4).…”