The immunopotentiating activity of neisserial porins, the major outer membrane protein of the pathogenic Neisseria, is mediated by its ability to stimulate B cells and up-regulate the surface expression of B7-2. This ability is dependent on MyD88 and Toll-like receptor (TLR)2 expression, as demonstrated by a lack of a response by B cells from MyD88 or TLR2 knockout mice to the porins. Using previously described TLR2-dependent reporter constructs, these results were confirmed and were shown to be due to induction of NF-κB nuclear translocation. This is the first demonstration of known vaccine adjuvant to stimulate immune cells via TLR2.

Neisserial porins are strong immune adjuvants and B cell activators. The effect of neisserial porin PorB on activation-induced cell death was investigated, as a potential additional mechanism of the porin's immunopotentiating ability. Neisserial porins interact with target cells to localize intracellularly in the mitochondrial compartment without negatively affecting cellular survival. Pretreatment with Neisseria meningitidis PorB porin decreased or abrogated the mitochondrial damage induced by apoptotic stimuli. In addition, end stage determinants of apoptosis, including DNA breakdown, were diminished by PorB. Immunoprecipitation experiments revealed that PorB interacts with the mitochondrial porin VDAC (voltage-dependent anion channel). The mechanism of the antiapoptotic effect of neisserial porins could be explained by the proteinprotein interaction of PorB with VDAC, similar to the interaction of VDAC with antiapoptotic Bcl-2 proteins, resulting in an enhancement of cell survival and continued activation of B cells.cell death ͉ voltage-dependent anion channel (VDAC) ͉ membrane potential ͉ staurosporine N eisserial porins, meningococcal PorA (class 1 protein) or PorB (class 2 or 3 proteins) or gonococcal protein IA or protein IB, are the major outer membrane protein of the pathogenic Neisseriaceae (1). They act as pores and are essential for organism survival. Interestingly, we and other investigators have demonstrated that these proteins act as immune stimulants and adjuvants (2-4) and can induce a T cell-dependent immune response against cell independent antigens (5-8). The mechanism of the adjuvant activity of neisserial porins recently has been elucidated, correlating with the porins' ability to upregulate the expression of the costimulatory molecule, B7-2, on the surface of B cells (and possibly other antigen-presenting cells) (6,8). Moreover, neisserial porins are potent B cell mitogens and act synergistically with CD40 or B cell receptor ligation to induce B cell proliferation and Ig secretion (6, 9). † Stimulation of immune cells normally increases their susceptibility to activation-induced cell death or apoptosis (10). Neisserial porins activate B cells as a probable mechanism of their adjuvant activity. If the porins also increased the susceptibility of B cells to apoptosis, this obviously would attenuate their immunopotentiating ability. Therefore, we investigated the ability of neisserial porins to affect the susceptibility of various cell types to apoptosis to determine whether another mechanism of the porins' adjuvant activity is to prevent B cell (and͞or antigen-presenting cell) apoptosis.If neisserial porins decreased the susceptibility of immune cells to apoptosis, what could be the possible mechanisms? It has been demonstrated that mitochondria and mitochondrial factors are intimately connected to the process of apoptosis (11). The mechanism of action of certain apoptotic stimuli, such as Fas receptor ligation or drugs like staurosporine (STS), involves opening of the mitochondrial permeabil...

SummaryThe neisserial porins are the major protein components of the outer membrane of the pathogenic Neisseria (N. meningitidis and N. gonorrhoeae). They have been shown to be able to enhance the immune response to poorly immunogenic substances (e.g., polysaccharides, peptides, glycolipids, etc.). To explore the basis of their potent adjuvant activity, the effect of the neisserial porins on T-B cell interactions and T cell costimulation was examined. Neisserial porins increased the surface expression of the costimulatory ligand B7-2 (CD86) but did not affect the expression of B7-1 (CD80). In addition, incubation with the neisserial porins increased the T lymphocyte costimulatory ability ofB lymphocytes, which was inhibited by anti-B7-2 but not anti-B7-1 monoclonal antibodies. Upregulation of B7-2 on the surface ofB lymphocytes may be the mechanism behind the immunopotentiating activity of neisserial porins. p rotein IA (PIA) and protein IB (PIB) of Neisseria gonorrhoeae and class 1, 2, or 3 proteins of N. meningitidis (C1, C2, and C3 respectively) are the most abundant neisserial outer membrane proteins (1). These proteins function as porins (2--4), share significant homology (5-9), and are members of the gram-negative porin superfamily (10). Neisserial outer membrane vesicle vaccines and purified neisserial porin vaccine candidates induce immune responses in humans and animals without the addition of exogenous adjuvants (11)(12)(13)(14). Neisserial porin preparations augment the humoral immune response to poorly immunogenic substances, for example, peptides, and induce a T cell-dependent immune response for normally T cell-independent antigens, for example, polysaccharides (15-18). Meningococcal OMV, mainly consisting of the class 2 protein, are used as carriers to boost the immune response towards the Haemophilus influenzae polysaccharide capsule in the recently licensed H. influenzae type b vaccine (15). The inclusion of purified PIA, PIB, C1, or C3 proteins in noncovalent complexes containing group C meningococcal capsular polysaccharides (CPS) greatly improves the antibody response in immunized mice to the polysaccharide compared with the 1Abbreviations used in this paper: CPS, group C meningococcal capsular polysaccharide; ICAM-1, intraceUular adhesion molecule-I; PIA, PIB, protein IA, IB, respectively; Th, T-helper.Part of this work was presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy, Sept. 17-20, 1995, San Francisco, CA. anti-CPS response in mice immunized with CPS alone (17). Neisserial porins are used as adjuvants in anti-melanoma cancer vaccines to augment the immune response to GM2 and GD3, two gangliosides present at much higher levels on malignant melanoma cells compared with normal human melanocytes (18).We postulated that the porins' adjuvant ability could be related to their effect on interactions between T and B lymphocytes, thereby increasing T cell involvement in the immune response. In the current model ofT lymphocyte stimulation, two sets of signals bet...

A T cell-dependent immune response to group C meningococcal capsular polysaccharide (CPS) can be elicited when CPS is conjugated to the class 3 neisserial porin (CPS-porin). Treatment of CPS-porin-immunized mice with B7-2 blocking monoclonal antibody (MAb) caused a dramatic reduction in the CPS-specific IgG response, treatment with anti-B7-1 MAb had no effect, and concurrent blockade of B7-1 and B7-2 resulted in a synergistic abrogation of the CPS-specific IgG response while the CPS IgM response was unaffected. Anti-CD40L MAb treatment caused a significant reduction of both CPS-specific IgG and IgM levels. In contrast, blockade of CTLA4 interactions resulted in increases in both CPS IgG and IgM responses in CPS-porin-immunized mice. These data support the hypothesis that the ability of neisserial porins to improve the immune response to poorly immunogenic antigens (e.g., polysaccharides) is related to porin-induced increases in B7-2 expression on antigen-presenting cells and enhanced B/T cell interactions.

Alternative splicing (AS) using a sole gene to express multiple transcripts with diverse protein coding sequences and/or RNA regulatory elements raises genomic complexities. In the nervous system, several thousand AS events play important roles in ion transportation, receptor recognition, neurotransmission, memory, and learning. Not surprisingly, AS influences human physiology, development, and disease. Many research studies have focused on aberrant AS in nervous system diseases, including Parkinson's disease (PD), the second most common progressive neurodegenerative disorder of the central nervous system. PD affects the lives of several million people globally. It is caused by protein aggregation, such as in Lewy bodies, and the loss of dopaminecontaining neurons in the substantia nigra of the midbrain. To our knowledge, six genes, including PARK2, SNCAIP, LRRK2, SNCA, SRRM2, and MAPT, are involved in aberrant AS events in PD patients. In this review, we highlight the relevance of aberrant AS in PD and discuss the use of an aberrant AS profile as a potential diagnostic or prognostic marker for PD and as a possible means of applying therapy.

Myricetin has novel immunopharmacological activity, and modulation of DCs by myricetin may be an attractive strategy for the treatment of inflammatory and autoimmune disorders, and for transplantation.

T lymphocytes from a majority of patients with urogenital gonococcal disease (67%-80%) proliferated on incubation with gonococcal porin (Por), compared with minimal induced proliferation of T lymphocytes from normal volunteers. A significant increase in Por-specific interleukin (IL)-4-producing CD4+ T helper lymphocytes was seen in patients with mucosal gonococcal disease and not in normal controls. Similar results were observed in CD8+ T lymphocytes from these patients. There was no measured increase in IL-2, IL-10, IL-12, interferon-gamma, or tumor necrosis factor-alpha production by T lymphocytes from infected subjects on incubation with Por. Concomitant increases in IL-4 production in T lymphocytes from infected subjects expressing the mucosal addresin VLAalpha4/beta7 on their surface were also observed on Por incubation, but the increases were similar in T lymphocytes that were VLAalpha4/beta7 negative. In conclusion, mucosal gonococcal disease can induce Por-specific circulating T lymphocytes with a Th2 phenotype, and a portion of these Por-specific T lymphocytes can potentially traffic to mucosal surfaces.

BackgroundDendritic cells (DCs) are major modulators in the immune system. One active field of research is the manipulation of DCs as pharmacological targets to screen novel biological modifiers for the treatment of inflammatory and autoimmune disorders. Acetylcorynoline is the major alkaloid component derived from Corydalis bungeana herbs. We assessed the capability of acetylcorynoline to regulate lipopolysaccharide (LPS)-stimulated activation of mouse bone marrow-derived DCs.Methodology/Principal FindingsOur experimental data showed that treatment with up to 20 µM acetylcorynoline does not cause cytotoxicity in cells. Acetylcorynoline significantly inhibited the secretion of tumor necrosis factor-α, interleukin-6, and interleukin-12p70 by LPS-stimulated DCs. The expression of LPS-induced major histocompatibility complex class II, CD40, and CD86 on DCs was also decreased by acetylcorynoline, and the endocytic capacity of LPS-stimulated DCs was restored by acetylcorynoline. In addition, LPS-stimulated DC-elicited allogeneic T-cell proliferation was blocked by acetylcorynoline, and the migratory ability of LPS-stimulated DCs was reduced by acetylcorynoline. Moreover, acetylcorynoline significantly inhibits LPS-induced activation of IκB kinase and mitogen-activated protein kinase. Importantly, administration of acetylcorynoline significantly attenuates 2,4-dinitro-1-fluorobenzene-induced delayed-type hypersensitivity.Conclusions/SignificanceAcetylcorynoline may be one of the potent immunosuppressive agents through the blockage of DC maturation and function.