Characterization of specific immunoglobulin G (IgG) and its subclasses (IgG1 and IgG2) against the 23-valent pneumococcal vaccine in a healthy adult population: proposal for response criteria

Abstract

The aim of the study was to standardize an enzyme-linked immunosorbent assay (ELISA) method for the quantification of immunoglobulin G (IgG) and its subclasses (IgG1 and IgG2) against the 23-valent pneumococcal vaccine and to establish the criteria for a normal response to the vaccine. Forty healthy individuals (20 women and 20 men; mean age, 29 years) were studied. All were vaccinated with the 23-valent pneumococcal vaccine; blood samples were drawn just prior to and 3 weeks after immunization. Quantification of specific IgG and its subclasses was performed by an ELISA with the vaccine as the antigen. The linearity of the ELISA method was demonstrated by the similar slopes of the linear regression lines generated from the titration of sera with different antibody concentrations. The specificity of the antibodies against the vaccine was demonstrated by (i) an absorption test with pneumococcal vaccine, (ii) a cross-reactivity experiment with Haemophilus influenzae type b polysaccharide, and (iii) affinity chromatography with protein A-Sepharose. Response to the vaccine was defined by using the lower level of the 90% probability interval (one-tailed) for postimmunizationspecific IgG, IgG1, and IgG2. By using this cutoff, responders were considered to be those with an absolute increase in antibody titers higher than 395 arbitrary units/ml for IgG, 0.350 A 450 units for IgG1, and 0.314 A 450 units for IgG2. Overall, 20 (50%) subjects had IgG, IgG1, and IgG2 responses, 9 (22.5%) had IgG and IgG2 responses, 4 (10%) had IgG1 responses, 3 (7.5%) had IgG and IgG1 responses, and 4 (10%) were nonresponders. Ninety percent of our population responded to the 23-valent pneumococcal vaccine. Up to 10% of healthy individuals may respond to an IgG subclass without significant increases in total IgG titers. The ELISA method that is described may be useful for evaluating the specific antibody response against polysaccharides.

Risk factors in HIV-1-infected patients developing repetitive bacterial infections: toxicological, clinical, specific antibody class responses, opsonophagocytosis and Fcγ RIIa polymorphism characteristics

“…[34]. This technique has been described extensively elsewhere [35]. All sera were absorbed with cell wall polysaccharide before test.…”

Specific Antibody Response Against the 23-Valent Pneumococcal Vaccine in Patients With α1-Antitrypsin Deficiency With and Without Bronchiectasis

“…Their results were compared with those of a control group comprised of 40 healthy, nonrelated volunteers (20 women, 20 men; age range, 21 to 48 years; mean age, 30 years), whose characteristics have been described previously. 11 None of the patients in either group had a history of prior pneumococcal immunization or known immunodeficiency. All subjects gave informed consent, and the study was approved by the Ethics Committee of the Vall d'Hebron Hospitals.…”

“…Reference values in our laboratory were as follows: IgG1, 2.61 to 10.81 g/L; IgG2, 1.12 to 4.08 g/L; IgG3, 0.22 to 2.88 g/L; and IgG4, 0.05 to 1.56 g/L. 11,12 Immunization All individuals were vaccinated with the same lot of PNU-Immune 23 polyvalent antipneumococcal vaccine (Lederle Laboratories; Pearl River, NY), 0.5 mL administered IM in the deltoids. This vaccine contained 25 g of each of the 23 specific capsular polysaccharides.…”

“…Total IgG, IgG1, and IgG2 levels specific to Streptococcus pneumoniae were determined by an ELISA test based on the method described by Metzger et al, 13 but modified by using the pneumococcal vaccine as antigen as described by Siber et al 14 This technique has been described extensively elsewhere. 11 Because the polyvalent pneumococcal vaccine may be contaminated with nonspecific cell wall polysaccharide, antibodies detected with this assay are not all necessarily protective against pneumococcal infection. 15 However, the aim of the present study was to investigate patients' ability to respond against polysaccharides in general, as a lack of specific antipolysaccharide response has been recognized as a humoral immunodeficiency that may promote recurrent respiratory infections.…”

“…The criterion for a patient to be considered a "responder" with any antibody isotype has been described elsewhere. 11 In brief, a responder for each of the isotypes evaluated was defined as an individual who showed an increase in his/her antibody titers Ͼ 395 U/mL, 0.350 A 450 units, and 0.314 A 450 units for specific antipneumococcal IgG, IgG1, and IgG2, respectively. These values correspond to the lower limit of the 90% probability intervals (two-tailed) of the log-transformed specific IgG, IgG1, and IgG2 postimmunization titers of the control group.…”