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ELISA Units (elisa + unit)

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Medical Sciences	100%

Selected Abstracts

Functional characteristics of antibodies induced by Arg-gingipain (HRgpA) and Lys-gingipain (Kgp) from Porphyromonas gingivalis

MOLECULAR ORAL MICROBIOLOGY, Issue 4 2001
T. Nakagawa
Arginine-specific gingipain (HRgpA) and lysine-specific gingipain (Kgp), enzymes produced by Porphyromonas gingivalis, may be candidates for an anti,P. gingivalis vaccine. The purpose of our study was to determine whether HRgpA and Kgp have opsonic target sites and whether these sites are available and accessible on intact P. gingivalis cells. Rabbits were used to generate polyclonal antibodies to both proteins. Animals were immunized and immunoglobulin G (IgG) fractions were isolated from preimmune and immune sera. Functional characteristics of the antibodies were assessed by determining antibody titers by enzyme-linked immunosorbent assay (ELISA), generating Western immunoblots, and measuring antibody enhancement of P. gingivalis opsonization, phagocytosis and killing by polymorphonuclear leukocytes (PMN) of intact cells of strains of P. gingivalis representative of the four serotypes. Strains studied included 33277 (serotype A), A7A1,28 (serotype B), W50 (serotype C) and 381 (serotype D). Both HRgpA and Kgp induced high titers of IgG antibody. Anti-HRgpA and anti-Kgp bound to both HRgpA and Kgp demonstrating a large proportion of shared antigenic epitopes. The two antibodies bound equally well to all four P. gingivalis serotypes with titers ranging from 77 to 205 ELISA units when compared to preimmune IgG set at 1 ELISA unit. The immunoblot patterns of binding of the two antibodies to HRgpA and Kgp and to sonicates of the four P. gingivalis serotypes were virtually identical. Both antibodies detected components in HRgpA at 27, 35 and 45 kDa and in Kgp at 27, 32, 35, 40 and 55 kDa. The antibodies also detected components at or near these same positions in addition to multiple high molecular mass components in the cell sonicates of P. gingivalis. Both proteins induced antibodies that significantly enhanced opsonization as assessed by chemiluminescence, with values ranging from 130 mV to 375 mV for anti-HRgpA IgG and from 240 mV to 475 mV for anti-Kgp IgG. Both antibodies significantly enhanced PMN-mediated bacterial killing of the four P. gingivalis serotypes, although the percentage of killing varied among the serotypes (24,81% for anti-HRgpA and 37,89% for anti-Kgp). Thus, both HRgpA and Kgp express opsonic target sites and induce high titers of antibodies that opsonize and enhance killing of all four serotypes of P. gingivalis. These two proteins appear to be potential candidate antigens for an anti,P. gingivalis vaccine. [source]

Prevalence of high antibody titers of pertussis in Turkey: reflection of circulating microorganism and a threat to infants

JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 3 2007
Berrin Esen
Abstract Acute pertussis infection among adults can cause its transmission to the larger population, especially to infants and young children, who can develop severe disease. In order to determine an age-dependent pertussis immune response, anti-pertussis toxin (PT) antibody was detected by the indirect enzyme-linked immunosorbent assay (ELISA) method in serum samples from 2,085 healthy subjects ranging in age from 6 months to ,60 years. Also included in the evaluation were responses to a questionnaire including sociodemographic characteristics, vaccination, and infection history. Titers of 50,99 ELISA units (EU)/mL and of ,100,EU/mL were accepted as indicative for recent exposure or infection. In addition, 30,EU/mL was estimated to be a sufficient titer in women of childbearing age to protect their newborns until administration of their first dose of pertussis vaccine. After the age of 4,5 years, presence of high-titered antibodies that increase with age might be a reflection of circulating infection and indicate the magnitude of the threat to infants. According to the questionnaires, in the groups younger than 15 years old, three to four doses of diphtheria toxoid-whole cell pertussis-tetanus toxoid (DwPT) were administered in 47.2 to 77.4%, 91.2 to 100.0%, and 83.5 to 100.0% of participants in Diyarbakir, Samsun, and Antalya, respectively. In addition, up to half of the expectant mothers we studied lacked a sufficient level of estimated antibody titers. To protect infants from life-threatening pertussis infection, improving vaccination coverage to ensure herd immunity and uniformly establishing coverage throughout the country are essential. Furthermore, revaccination with acellular vaccine for schoolchildren as well as for the households of pregnant women is recommended. J. Clin. Lab. Anal. 21:154,161, 2007. © 2007 Wiley-Liss, Inc. [source]

Serum IgG to heat shock proteins and Porphyromonas gingivalis antigens in diabetic patients with periodontitis

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2002
Tom J. Sims
Abstract Background: Past studies have reported a correlation between the presence and severity of periodontitis and serum antibody titers to species-specific antigens of Porphyromonas gingivalis or to cross-reactive antigens, such as lipopolysaccharide (LPS) and heat shock proteins (HSP), shared between P. gingivalis and other bacteria. Our recent study of periodontal treatment outcome in insulin-dependent (type 1) diabetes mellitus patients with severe periodontitis (IDDMI/periodontitis) resulted in two key findings: 1. serum glutamic acid decarboxylase autoantibody (GAD65 Ab) levels were significantly associated with periodontal pocket depth change (PDC) and 2. serum IgG titers to P. gingivalis cells were positively associated with GAD65 Ab level in seropositive (GAD65 Ab +) patients. We have therefore hypothesized that profiles of serum autoantibody levels and IgG titers, to P. gingivalis -specific antigens may be useful in assessing risk for refractory periodontitis in such patients. Aim: To determine whether PDC resulting from non-surgical periodontal treatment can be predicted using profiles of baseline IgG titers to P. gingivalisspecific antigens, human HSP, and GAD65. Methods: PDC was assessed two months after non-surgical periodontal treatment of 7 GAD65 Ab + and 11 GAD65 AbIDDM/periodontitis patients. Pretreatment titers to GAD65, recombinant human heat shock proteins (HSP90, HSP70, and HSP60), and various P. gingivalis antigens were measured using radioligand precipitation or enzyme-linked immunosorbent (ELISA) assays and compared to the same measurements for 154 recent-onset IDDM patients and 46 non-diabetic controls. Results: Median titers (ELISA units) to HSP90 and HSP70 were significantly higher than non-diabetic controls for GAD65 Ab + (p°= 0.002) and GAD65 Ab- (p =,0.034) IDDM/periodontitis patients, respectively. Multivariate regression analysis indicated significant partial correlation of PDC with log-transformed titers to HSP90 (r =,, 0.62, p = 0.008), HSP70 (r =,+ 0.62, p = 0.009), GAD65 (r =,, 0.60, p = 0.01) and P. gingivalis LPS (r = , 0.5 1, p = 0.04). Furthermore, hierarchical clustering of baseline profiles of log-transformed HSP90, HSP70, and GAD65 Ab titers sorted patients into two distinct clusters with significantly different median PDC (1.45 min, n = 10 vs. 0.65 min, n = 8; p = 0.016, Mann,Whitney). Conclusion: Pretreatment profiles of serum antibody titers to HSP90, HSP70, GAD65, and P. gingivalis LPS may be useful for predicting which patients with IDDM/periodontitis will have a poor response to non-surgical periodontal therapy. [source]