Ex Vivo Bactericidal Activity against Group C Neisseria meningitidis in Seronegative Subjects

Gómez-Lus, Marı́a Luisa; Aguilar, Lorenzo; Vázquez, Julio; Giménez, Marı́a José; Ruiz, Gabriel Fiol; Berrón, S.; Fuentes, Fernando; Prieto, J.

doi:10.1007/s150100070024

Cited by 3 publications

(3 citation statements)

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“…A previous publication described opsonophagocytic activity in seronegative subjects [10] in the screening phase of the clinical trial reported here. The current study describes opsonophagocytosis and complement-mediated bactericidal killing determined in ex vivo killing curves over a 3-year period following vaccination with the polysaccharide vaccine of group C Neisseria meningitidis.…”

Section: Introductionmentioning

confidence: 68%

“…In the screening phase of this trial, 12% of the screened subjects who were seronegative (bactericidal antibody titres < 1 : 8 and ELISA antibody titers < 2 µg/ml) demonstrated high bacterial killing activity [10], probably activated by antibodies at levels below the detection limit. In contrast, in this study, 16.6% (2/12) of seroprotected subjects did not have the capacity to kill bacteria in the ex vivo killing curves over the 3-year follow-up.…”

Section: Discussionmentioning

confidence: 99%

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Opsonophagocytosis versus Complement Bactericidal Killing as Effectors following Neisseria meningitidis Group C Vaccination

et al. 2003

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Section: Introductionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Opsonophagocytosis versus Complement Bactericidal Killing as Effectors following Neisseria meningitidis Group C Vaccination

et al. 2003

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“…meningitidis is efficiently phagocytosed by polymorphonuclear (PMN) cells (5,8,10), and antibodies specific for group A and C polysaccharides are bactericidal in the presence of peripheral blood polymorphonuclear leukocytes and complement (19). Monocytes can also phagocytose Neisseria species (12,13,16,23).…”

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Opsonophagocytosis of Fluorescent Polystyrene Beads Coupled to Neisseria meningitidis Serogroup A, C, Y, or W135 Polysaccharide Correlates with Serum Bactericidal Activity

Martinez

Pilishvili

Barnard

et al. 2002

Clin Vaccine Immunol

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We developed a polysaccharide-specific flow cytometric opsonophagocytic assay (OPA) for the simultaneous measurement of functional antibody to Neisseria meningitidis serogroups A, C, Y, and W135. OPA titers significantly correlated with serum bactericidal assay titers for all serogroups tested (mean r ‫؍‬ 0.96; P < 0.001). OPA could be used in meningococcal vaccine evaluation.Meningococcal disease continues to be a significant cause of morbidity and mortality in the United States and worldwide (3). The primary mechanism of protection from disease is through antibody-and complement-dependent bactericidal activity (9). Antibodies to capsular polysaccharides of groups A and C of Neisseria meningitidis have been shown to confer protection from meningococcal disease (1,7).N. meningitidis is efficiently phagocytosed by polymorphonuclear (PMN) cells (5,8,10), and antibodies specific for group A and C polysaccharides are bactericidal in the presence of peripheral blood polymorphonuclear leukocytes and complement (19). Monocytes can also phagocytose Neisseria species (12,13,16,23). The relative importance of opsonophagocytic killing as a defense mechanism against N. meningitidis has been previously demonstrated (2,4,18,20,22). Opsonophagocytic assays (OPA) offer several advantages over the standard serum bactericidal assay (SBA). OPA for other pathogens such as Streptococcus pneumoniae have been developed which are semi-automated, use noninfectious targets, provide useful laboratory correlates of protection, and can be multiplexed (14).This report describes a patent-pending multiplexed flow cytometric OPA for measurement of antibody-and complementdependent cell-mediated antimeningococcal activity against serogroups A, C, Y, and W135. Postvaccination sera were collected 1 month after immunization with a quadrivalent meningococcal vaccine (Menomune; Connaught Laboratories, Philadelphia, Pa). Sera from nonimmunized adults (n ϭ 15) and postvaccination adults (n ϭ 12) were obtained through the Emory University Donor Services, Atlanta, Ga., and used as quality controls (15). Sera were stored at Ϫ70°C and heat inactivated at 56°C for 30 min just before being tested, to inactivate endogenous complement activity. We compare this flow OPA technique to a previously standardized SBA (15).(Part of this study was presented at the 11th International Pathogenic Neisseria Conference, Nice, France, 1998.) Homologous capsular polysaccharide from meningococcal serogroups A, C, Y, and W135 (Connaught Laboratories) at a concentration of 1 mg/ml was oxidized by the addition of 218 l of a 0.046 M sodium periodate solution for 30 min, protected from light, at room temperature. The reaction was stopped by the addition of 0.1 ml of glycerol per ml of reaction solution. The polysaccharide solutions were then dialyzed overnight against 0.1 M sodium bicarbonate buffer (pH 8.0).Aliquots (100 l) from the commercial preparation of 1-m-diameter carboxylate-modified FluroSpheres (Molecular Probes, Eugene, Oreg.) were coupled with each oxidized meningoc...

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Serologic correlates of protection for evaluating the response to meningococcal vaccines

Balmer

Borrow

2004

Expert Review of Vaccines

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Meningococci cause serious disease worldwide and the organism remains the most common cause of bacterial meningitis in children and young adults. The only effective means of controlling disease is through vaccination. Although polysaccharide vaccines have been available for serogroup A, C, Y and W135 for many years, serogroup C polysaccharide-protein conjugate vaccines have only recently been licensed in many countries. Conjugate vaccines for combinations of serogroup A, C, Y and W135 are progressing through clinical trials and major efforts are being made to develop a safe and efficacious vaccine against serogroup B. To assess the quality of the immune response after vaccination, laboratory correlates of protection are needed. For serogroups A and C, serum bactericidal antibody is a well established predictor for protection but for serogroup B, other mechanisms besides serum bactericidal antibody may also be involved in conferring protection against disease. The serologic correlates of protection for evaluating the response to meningococcal vaccines are described in this review.

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Ex Vivo Bactericidal Activity against Group C Neisseria meningitidis in Seronegative Subjects

Abstract: The addition of functional tests to the classical serological determination increases the evidence of previous contact with N. meningitidis antigens by 12%.

Cited by 3 publications

References 19 publications

Opsonophagocytosis versus Complement Bactericidal Killing as Effectors following Neisseria meningitidis Group C Vaccination

Opsonophagocytosis versus Complement Bactericidal Killing as Effectors following Neisseria meningitidis Group C Vaccination

Opsonophagocytosis of Fluorescent Polystyrene Beads Coupled to Neisseria meningitidis Serogroup A, C, Y, or W135 Polysaccharide Correlates with Serum Bactericidal Activity

Serologic correlates of protection for evaluating the response to meningococcal vaccines

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