Cells producing antibody to measles and herpes simplex virus in cerebrospinal fluid and blood of patients with multiple sclerosis and controls.

The B cell response against measles and herpes simplex virus (HSV) was evaluated in cerebrospinal fluid (CSF) and peripheral blood from patients with multiple sclerosis (MS) and controls by enumeration of cells secreting anti-measles and anti-HSV antibodies of IgG, IgA and IgM isotypes. We used a nitrocellulose immunospot assay which enables parallel enumeration of numbers of cells secreting total IgG, IgA and IgM. Anti-measles IgG antibody-secreting cells were present in CSF from 21 of 24 MS patients (mean 24 cells/10(4) mononuclear cells), and against HSV in CSF from seven of eight patients (mean 23/10(4) cells). No antibody-secreting cells were detectable in the patients' blood. Ten MS patients examined were negative for cells in CSF and blood producing anti-measles antibodies of IgA and IgM isotypes. Anti-measles IgG antibody secreting cells were also found in CSF from four of 18 controls, and anti-HSV IgG antibody-secreting cells in six of 13, especially in patients with subacute or chronic inflammatory nervous system diseases. Our results confirm that viral antibodies in MS are produced within CSF and that this B cell response is preferentially sequestered to this compartment. Whether this viral B cell response in MS reflects specific activation due to persistence of viral antigens or an epiphenomenon remains to be clarified.     

Enumeration of human peripheral blood lymphocytes secreting immunoglobulins of major classes and subclasses in healthy children and adults

The reverse enzyme-linked immunospot assay was modified to enumerate peripheral blood mononuclear cells (PBMC) secreting IgG1–4, IgA1–2, and IgM. Anti-human IgG F(ab')₂ and mouse monoclonal antibodies specific to each of the isotypes were used as solid-phase capture antibodies and developing antibodies, respectively. Although attempts were also made to detect IgD- and IgE-secreting cells (SC), their numbers in the peripheral blood were too few to be reliably estimated. The assay was applied to study healthy subjects including 21 neonates within 3 days of birth, 44 1- to 48-month-old children, and 32 adults. Sixty percent of these neonates had IgM SC in small numbers (<20 per 10⁶ PBMC), but only three neonates had IgSC of other isotypes. In contrast, by 1–2 months of age children had IgSC of all isotypes, including IgA2 and IgG4, often in higher numbers than adults. The relative frequencies of IgSC were IgA1 > IgG1 > IgM > IgG2 > IgG3 > IgG4 > IgA2 in the children and IgA1 > IgG1 > IgA2 > IgM > IgG4 > IgG2 > IgG3 in the adults. The order of the serum concentrations in the adults was IgG1 > IgG2 > IgA > IgM > IgG4 > IgG3. No correlation was found between the serum level and the IgSC number of individual isotypes (except for serum IgA and IgA1-SC). This new methodology should facilitate investigating the current status of immunoglobulin synthesis and the Ig repertoire in adults and children, in health and in disease.Dedicated to the memory of Dr. Charles Reimer.     

Spontaneous antibody-secreting cells against DNA and common environmental antigens in systemic lupus erythematosus

Cells spontaneously secreting IgG or IgM antibodies to DNA or to common environmental antigens--influenza virus haemagglutinin, adenovirus hexon and mannan from Candida albicans--have been enumerated by ELISA spot in blood from patients with systemic lupus erythematosus (SLE) and normal donors. Mean values were raised for all antigens in the disease, with those for DNA being no greater than for the other antigens. In normal donors, levels of IgM-secreting cells were similar for DNA and the environmental antigens whereas virtually no IgG anti-DNA secreting cells were found. When results were expressed relative to total numbers of IgG or IgM-secreting cells, the differences between the groups disappeared or were greatly reduced in all systems except IgG anti-DNA. These findings are consistent with a requirement for both polyclonal activation and a self-antigen response in the production of IgG autoantibodies in SLE.     

Kinetics and isotype distribution of parasite-specific antibody responses in the spleen of mice during primary infection with Schistosoma mansoni. Studies at the single-cell level

The solid-phase enzyme-linked immunospot assay has been adapted for enumerating cells secreting antibodies to crude antigenic extracts from the main developmental stages of Schistosoma mansoni. The frequencies of splenocytes secreting antibodies reactive with soluble antigenic extracts from cercariae, adult worms, and eggs, were examined in C57BL/6 mice during the first 12 weeks of a primary infection with S. mansoni. Despite the existence of cross-reactive moieties present in these antigenic preparations, the characteristics of the responses monitored differed with regard to kinetics, magnitude, and/or isotype distribution. The responses peaked between 8 and 10 weeks of infection, were characterized by a predominance of cells secreting IgM antibodies against all three antigens, and followed the patterns IgM greater than IgA greater than IgG for cercariae, IgM greater than IgG greater than IgA for adult worms and IgM greater than IgG greater than IgA for egg extracts. On the other hand, these patterns were not always reflected in serum, especially for cercariae-reactive circulating IgG and IgA responses. When examined for numbers of total IgM-, IgG- and IgA-producing cells, the spleen of S. mansoni-infected mice was shown to display considerable numbers of immunoglobulin-producing cells in all three isotypes studied. The most spectacular increases were noted for IgG-secreting cells (more than 10-fold) and for IgM-secreting cells (up to 6-fold) 4 weeks after initial cercarial exposure. Taken together, these observations indicate that primary infection with S. mansoni results in early immunoregulatory alterations which may contribute to the maintenance of specific as well as nonspecific B cell hyperactivity.(ABSTRACT TRUNCATED AT 250 WORDS)     

T cell dependent differentiation of human B cells: direct switch from IgM to IgE, and sequential switch from IgM via IgG to IgA production.

Ig production by splenic human B cells that express different surface Ig isotypes were analysed in limiting dilution cultures. Therefore, FACS sorted IgM+, IgG+ and IgA1+ B cells were stimulated with PMA-activated EL4 thymoma cells as helper cells in the presence of IL-2 and IL-4. We found that at least every second B cell responded in vitro and secreted the antibody corresponding to its surface Ig isotype. IgE secreting cells developed from surface IgM+ D+ cells (1/31 to 1/167), but not from IgG+ or IgA1+ cells (much less than 1/5000). Negative signalling of the IgM+ B cells by addition of anti-IgM antibodies into the cultures reduced the number of single IgM producing cells by greater than 85%, and completely inhibited IgE switch. In contrast, anti-IgG and anti-IgA antibodies did not reduce the IgE response. The results indicate a direct switch from IgM to IgE secretion in vitro. In contrast to IgE, IgA secreting cells developed from IgM+D+ (1/30 to 1/51) and from IgG+ B cells (1/14 to 1/25). Negative signalling of the IgG+ B cell subset within total B cells by anti-IgG antibodies suppressed the development of IgG as well as IgA producing cells, but did not inhibit IgM and IgE responses. This indicates a sequential switch from IgM via IgG to IgA. Taken together, this study indicates that IgE secreting cells are derived directly from IgM+D+ B cells by non-sequential switching, whereas IgA producing cells preferentially develop by sequential switching via IgG+ B cells.     

Human anti-acetylcholine receptor antibodies use variable gene segments analogous to those used in autoantibodies of various specificities

The production of autoantibodies to the nicotinic acetylcholine receptor are responsible for many of the neurological symptoms observed in myasthenia gravis. An understanding of the structural organization of the anti-receptor antibodies may help to define the role of these antibodies in the pathogenesis of this disease. The nucleotide sequences of the heavy and light chains of three human monoclonal anti-receptor antibodies isolated from peripheral blood lymphocytes from two patients with myasthenia gravis were analyzed. In addition, the structure of an anti-idiotypic antibody was studied. The V_H and V_L gene segments used in the anti-receptor antibodies appear to be derived from the same repertoire as gene segments that have been found in other autoantibodies isolated from patients with various autoimmune diseases. The IgM anti-receptor antibodies are direct copies of germline gene segments, while the structures of the IgG anti-receptor antibody and the anti-idiotypic antibody appear to be mutated suggesting that they have undergone antigenic selection.     

IgA hybridomas: A method for generation in high numbers

An immunization regimen has been developed which yields a high frequency of hybridomas producing IgA isotype, antigen-specific antibody when spleen cells from immunized mice are fused with non-immunoglobulin secreting murine myeloma cells. Germfree BALB/c mice were carrier-primed with sheep erythrocytes (SRBC) by gastric intubation (GI) for 2 consecutive days followed 1 week later by GI with trinitrophenyl (TNP)-haptenated SRBC. After 7 days, spleen cells were fused with non-immunoglobulin secreting myeloma cells (X63-Ag8.653), and 2–3 weeks later, culture wells were scored for hybrid clones. Of 240 culture wells plated, 157 wells (65.4%) exhibited clones producing anti-TNP antibodies as determined by enzyme-linked immunosorbent assay. A total of 50 specific cell lines were established, of which 27 clones (54%) produced IgA isotype anti-TNP antibodies, while the anti-TNP antibodies produced by the remaining 23 clones were approximately equally distributed between the IgM and IgG isotypes. The IgA and IgM monoclonal antibodies were more effective in hemagglutinating TNP-SRBC than were IgG isotype antibodies. This study describes a method for production of a high number of antigen-specific IgA hybridomas which will allow production of IgA monoclonal antibodies to important antigens on mucosally-associated pathogens, and thus allow elucidation of functions of IgA antibody at mucosal surfaces.     

Normal human immunoglobulin suppresses experimental myasthenia gravis in SCID mice.

Serum IgM has been shown to participate in the control of IgG autoreactivity in healthy subjects. We have recently shown that an immunoglobulin preparation of pooled normal human IgM (IVIgM) contains anti-idiotypic antibodies against disease-associated IgG autoantibodies in autoimmune patients and protects rats from experimental autoimmunity. The aim of the present study was to asses the in vitro and in vivo immunomodulatory effects of IVIgM in comparison with IgG, in SCID mice reconstituted with thymic cells from a myasthenia gravis patient. Non-leaky SCID mice were injected i.p. with 60 x 10(6) thymic cells from a patient with myasthenia gravis and 1 day later boosted with 10(6) irradiated acetylcholine receptor (AchR)-expressing TE671 cells. On days 14, 21 and 28, mice were treated with IVIgM or with equimolar amounts of human serum albumin. The level of anti-AchR antibodies in the sera of three out of four IgM-treated animals was less than 1 nM. Further, there was a significant decrease in the loss of endplate AchR on the diaphragms of IgM-treated SCID mice. These findings indicate that pooled normal IgM exerts an immunoregulatory role in experimental myasthenia gravis, and suggests that IgM may be considered as an alternative approach in the therapy of autommune diseases.     

Cells producing antibodies specific for myelin basic protein region 70-89 are predominant in cerebrospinal fluid from patients with multiple sclerosis.

Cells secreting antibodies against guinea pig myelin and synthetic myelin basic protein (MBP) peptides were evaluated in cerebrospinal fluid (CSF) and blood from patients with multiple sclerosis (MS) and a variety of other neurological diseases (OND). The peptides used, reproducing amino acid sequences 1-20, 70-89, 108-126, or 157-166 of MBP, were selected on the basis of their hydrophilic and encephalitogenic properties. Low numbers of cells secreting IgG antibodies against myelin or each of the MBP peptides (about 1 per 50,000) were detected in peripheral blood, with no difference between MS and OND. In CSF, cells secreting IgG antibodies to MBP 70-89 were more frequently (p = 0.007) detected in patients with MS (1/380 IgG-secreting cells on average) than in patients with OND (1/2083 IgG-secreting cells on average). The frequencies of cells secreting antibodies against myelin or the three other MBP peptides were similar in MS and OND. Thus, evaluation of B cell immunity at the cellular level indicates that MBP 70-89 is an immunodominant B cell epitope in MS. It is not clear whether this intrathecal anti-MBP 70-89 IgG antibody response has any pathogenetic relevance in MS or is the result of myelin breakdown.     

Multiple Sclerosis: Cells Secreting Antibodies Against Myelin-Associated Glycoprotein are Present in Cerebrospinal Fluid

We evaluated the B-cell response in cerebrospinal fluid (CSF) and blood by enumerating cells secreting antibodies to myelin-associated glycoprotein (MAG) and, for reference, to myelin basic protein (MBP), two myelin components which may constitute targets for autoimmune attack in multiple sclerosis (MS). Among 25 untreated MS patients, 12 had cells in CSF secreting anti-MAG IgG antibodies (mean value 1 per 1429 CSF cells) and three also had cells secreting anti-MAG antibodies of the IgM isotype but at lower levels. In CSF from 2 out of 10 MS patients examined, anti-MAG and anti-MBP IgG antibody-secreting cells were present concurrently. Antibody-secreting cells were less frequent in blood and bone marrow, reflecting compartmentalization to CSF. Anti-MAG antibody-secreting cells were found in CSF from only 1 out of 27 control patients. The intrathecal production of anti-MAG and anti-MBP antibodies may be important in the pathogenesis of MS.     

Proportions of immunoglobulin isotypes in paralytic poliomyelitis and after vaccination

Immunoglobulin isotype composition of poliovirus antibodies was studied by isotype-specific solid-phase radio-immunoassay (RIA) in four patients with paralytic poliomyelitis, five adults receiving live poliovirus vaccine as a booster immunization, and seven children receiving first doses of inactivated poliovirus vaccine. In paralytic poliomyelitis serum and cerebrospinal flind (CSF) poliovirus antibodies were mainly of IgG1, IgG3, and IgA isotypes. IgM antibodies were found in sera but not in CSF. Either IgG2 and IgG4 antibodies were undetectable or the titers were low. In adults who had received live trivalent poliovirus vaccine, antibodies against poliovirus type 3 were detected in IgG1 (53% of total antibodies), IgG3 (25%), IgM (9%), IgA (8%), IgG2 (3%), and IgG4 (2%) isotypes. In prevaccination and late postvaccination sera the share of IgG3 antibodies was exceptionally high (35%). In children who received inactivated poliovirus vaccine, antibodies developed in IgG1 (53–61% of total antibodies for poliovirus types 1, 2, and 3), IgG3 (12–21%), and IgM (23–33%) isotypes. Antibody levels in IgG2, IgG4, and IgA isotypes were low and observed only in a few cases. Like other viral antibodies IgG1 and IgG3 isotypes were the major IgG subclasses in poliovirus antibodies.     

Structural properties of the glycoplasmanylinositol anchor phospholipid of the complement membrane attack complex inhibitor CD59.

Peripheral blood B cells from patients with systemic autoimmune disease and healthy volunteers were immortalized using EBV and the frequencies of B cell precursors that produced immunoglobulin class-specific antibodies against anti-nRNP, a specific marker for mixed connective tissue disease, were assessed using limiting dilution analysis. The frequencies of EBV-induced B cell precursors that produced IgG anti-nRNP were correlated closely with the serum titres of the corresponding autoantibodies, which indicates that B cell precursors that produced potentially pathogenic autoantibodies could be immortalized from the peripheral blood of the patients by EBV. In contrast, the frequency of EBV-induced B cell precursors that produced IgM anti-nRNP in patients with systemic autoimmune disease was comparable to that in healthy volunteers and greater than those that produced IgG and IgA anti-nRNP. Moreover, many of the clones that produced IgM antibodies against nRNP reacted with other autoantigens, such as double-stranded DNA, single-stranded DNA and rabbit IgG. These polyreactive IgM antibodies are believed to belong to the 'natural antibodies', to be coded by the germline immunoglobulin V genes, and to react with evolutionarily conserved structural cellular components, including nRNP. Our finding that nRNP is one of the target antigens for this polyreactive autoantibody may lead to the elucidation of the origin of the pathogenic IgG and IgA anti-nRNP antibodies found in sera from patients with systemic autoimmune diseases.     

Distribution of IgM, IgA and IgG secreting cells in the tissues of normal and tumour-bearing mice.

The levels of IgM, IgA and IgG secreting cells were examined in control, Corynebacterium parvum-stimulated and tumour-bearing, normal and athymic (Nu/Nu) mice. The percentage of IgA to IgM or IgG secreting cells is relatively higher in peripheral blood than in the spleen or peritoneum of normal mice. Within tumours, irrespective of their degree of vascularization and immunogenicity, the pattern of Ig secreting cells in similar to that seen in peripheral blood and different from that in spleen and peritoneum even in athymic mice. Intraperitoneal injection of C. parvum changes the relative percentages of Ig secreting cells in the peritoneal cavity to resemble that seen in the peripheral blood and tumours. It appears that Ig secreting cells extravasate from peripheral blood in a non-isotype specific manner into sites of chronic stimulation.     

Elevated Levels and Different Repertoire Profile of Colostral Anti-LPS Antibodies May Have a Significant Role in Compensating Newborn Immunity

A high prevalence of systemic infections caused by enterobacteria such as Escherichia coli is observed during the neonatal period. Lipopolysaccharide (LPS) is one of the major factors responsible for septic shock caused by these Gram-negative bacteria. We have recently demonstrated the presence of anti-LPS immunoglobulin (Ig)G antibodies in cord blood with a repertoire identical to that found in maternal serum. In the present study, we analyzed anti-LPS O111 antibody isotypes in maternal serum and colostrum from mothers and in cord serum from their respective full-term (n = 30) and preterm (n = 13) neonate infants. The main isotype found in serum samples from mothers of term infants was IgM (range between 28 and 54 mg/l), followed by IgA (1-2 mg/l) and IgG (2-3 mg/l). The range of IgG antibody concentrations in cord blood was between 2 and 3 mg/l, as a result of placental transfer. A novel observation in our study was that the LPS bands recognized by colostral antibodies were completely different from those recognized by IgG in serum. Colostral IgA antibodies recognized several bands not bound by serum IgG antibodies from the respective maternal serum, independently of the antibody quantity. In addition, we verified the pattern of LPS recognition by serum IgA and colostral IgA antibodies was identical, what suggested that the antibody isotype found in serum could probably be derived from differentiated IgA-positive cells which were homing to the mucosa through the mucosal homing mechanism. Identical pattern of recognition was obtained comparing the IgA and IgM isotypes in colostrum. Slight differences in the pattern of recognition were found between colostral and serum IgM antibodies. The fact that colostral antibodies recognize much more bands than serum antibodies may be important for the host to mount an effective immune response in the intestinal lumen, in order to prevent excessive absorption of LPS, reducing possible systemic effects caused by the molecule.     

Modulation of natural IgM autoantibodies to oxidative stress-related neo-epitopes on apoptotic cells in newborns of mothers with anti-Ro autoimmunity

At birth, the human immune system already contains substantial levels of polymeric IgM, that include autoantibodies to neo-epitopes on apoptotic cells (ACs) that are proposed to play homeostatic and anti-inflammatory roles. Yet the biologic origins and developmental regulation of these naturally arising antibodies remain poorly understood. Herein, we report that levels of IgM-antibodies to malondialdehyde (MDA) protein adducts, a common type of in vivo generated oxidative stress-related neoepitope, directly correlate with the relative binding of neonatal-IgM to ACs. Levels of IgM to phosphorylcholine (PC), a natural antibody prevalent in adults, were relatively scant in cord blood, while there was significantly greater relative representation of IgM anti-MDA antibodies in newborns compared to adults. To investigate the potential interrelationships between neonatal IgM with pathogenic IgG-autoantibodies, we studied 103 newborns born to autoimmune mothers with IgG anti-Ro (i.e., 70 with neonatal lupus and 33 without neonatal lupus). In these subjects the mean levels of IgM anti-Ro60 were significantly higher than in the newborns from non-autoimmune mothers. In contrast, levels of IgM anti-MDA in IgG anti-Ro exposed neonates were significantly lower than in neonates from non-autoimmune mothers. The presence or absence of neonatal lupus did not appear to influence the total levels of IgM in the anti-Ro exposed newborns. Taken together, our studies provide evidence that the immune development of the natural IgM-repertoire may be affected, and become imprinted by, the transfer of maternal IgG into the fetus.     

Kinetics and Isotype Profile of Rheumatoid Factor Production During Viral Infection: Organ Distribution of Antibody Secreting Cells

The kinetics and isotype profile of influenza virus-specific IgG antibodies were studied in correlation with the serum titre of IgG-reactive autoantibodies. An increased level of IgG isotype-specific, rheumatoid factor-type autoantibody secretion was observed in the late phase of the virus-specific memory response. These rheumatoid factors were specific for the IgG2a and IgG1 subclasses which dominated the anti-viral antibody response. As revealed by a preparative immunosorbent technique combined with isotype quantitation the majority of IgG2a- or IgG1-bound immunoglobulins isolated from the serum of virus-infected mice belonged to the same subclass as the target antibody. Comparison of the kinetics of appearance and the number of IgM-, IgG- and IgA-type IgG2a-reactive autoantibody secreting cells during the primary and memory anti-viral antibody responses showed isotype switch of IgM rheumatoid factor secreting cells predominantly to IgA. Localization of IgM and IgA antibody secreting cells demonstrated the wide organ distribution of IgM-type rheumatoid factor secreting cells. On the contrary, IgA rheumatoid factor production was observed only in Peyer's patches and at the site of the local virus-specific immune response, i.e. in mediastinal lymph nodes and in the lung. These results demonstrate that B cells specific for self IgG are activated and differentiated in concert with the virus-specific antibody response in similar microenvironments. The predominant involvement of the mediastinal lymph nodes and the spleen in the production of IgG2a-specific IgM-type autoantibodies suggest a regulatory function of this type of autoantibodies in modulating IgG2a production in both systemic and local anti-viral immune responses. The results also suggest a strictly regulated rheumatoid factor production which, however, can be unbalanced by repeated viral infections resulting in the escape of high affinity, isotype-switched autoantibodies.     

Spontaneous class switching and B cell hyperactivity increase autoimmunity against intracellular self antigen in Lyn-deficient mice

IgG autoantibodies cause pathology due to their ability to bind self antigens. However, the extent to which the initial B cell activation and isotype switching is antigen-driven is unclear and it has been widely proposed that intrinsic B cell hyperactivity may be a contributing factor. To explore this issue we generated mice with B cell hyperactivity secondary to deficiency in the src kinase Lyn that also expressed a gene-targeted anti-hen egg lysozyme Ig construct (VDJkappa) capable of class switching to all isotypes. The B cell hyperactivity caused spontaneous hypersecretion of antibodies and class switching to IgM, IgA, IgG1 and IgG3 isotypes in the absence of self antigen, and this persisted as an autoimmune phenomenon in the presence of intracellularly expressed hen egg lysozyme. Exaggerated class switching was also unaffected by antigen in vitro. These findings show that systemic high-avidity intracellular self antigens do not induce self tolerance in the face of B cell hyperactivity. Under these circumstances, spontaneous activation of hyperactive B cells leads to isotype switching and the development of high titres of IgG autoantibodies against intracellular proteins.     

Quantitation of Antibody-Secreting Cells in the Blood after Vaccination with a Haemophilus influenzae Type b Conjugate Vaccine

The human B-lymphocyte response to proiein-conjugated polysaccharide antigens has not previously been studied at the cellular level. In order to do so, we developed and evaluated haemolytic plaque-forming cell assays detecting Haemophilus influenzae type b (Hib) capsular polysaccharide-specific antibody-secreting cells (AbSC) of the isotypes IgM, IgG, and IgA. The appearance of AbSC in the blood after vaccimation of adults with diphtheria toxoid-conjugated Hib polysaccharide was investigated. AbSC were detected from post-vaccination day 5 to day 14.
IgA was the predominant isotype among these cells. IgM AbSC peaked slightly earlier (median day 7) than IgG and IgA AbSC (both day 8). On post-vaccination day 8 ihe numbers of AbSC were: IgA. 1217/10⁶ mononuclear cells (median); IgG, 211; and IgM, 30 ( n = 11). Similar isotype distribution has earlier been found after vaccination with pure capsular polysaccharides from Hib and pneumococci. The predominance of IgA AbSC in response to both conjugate and pure polysaccharide vaccines is probably due to reactivation of the same clones of IgA-committed memory B cells originally primed at the mucosa by natural exposure to the polysaccharide or cross-reacting antigens.     

Vaccination-Induced Circulation of Human B Cells Secreting Type-Specific Antibodies against Pneumococcal Polysaccharides

Indirect plaque-forming cell assays detecting B cells secreting antibodies against capsular pneumococcal polysaccharide (PPS) antigens are described. In healthy adult volunteers the total number of B cells secreting IgM antibodies against the antigens in a polyvalent PPS vaccine reached a maximum in the blood 6 days after in vivo immunization (mean: 552/10(6) mononuclear cells), whereas the highest concentration of IgG and IgA antibody-secreting cells (SC) were detected 7 days after immunization (means: 628 and 1691/10(6]. B cells secreting antibodies to PPS type 3 (PPS3), PPS8, PPS18C and C-polysaccharide (CPS)--a cell wall antigen common to all pneumococci--constituted 9%, 16%, 6% and 5% (means) of the total number of antibody SC respectively. While the majority of the anti-PPS-SC secreted IgA antibodies, the anti-CPS-SC almost exclusively secreted IgG. Pre-vaccination concentrations of anti-PPS were generally low in contrast to antibodies against CPS, which were present in high concentrations in all individuals. The discrepancy in the Ig class of the antibody SC is probably related to the difference in the pre-vaccination immunity against PPS and CPS.     

Ontogenic development of proliferative and polyclonal antibody and autoantibody responses to staphylococcal peptidoglycan, protein A and cell walls in mice

In the spleens of newborn mice, polyclonal IgM, IgG and IgA responses were low to protein A, cell walls (CW) and PWM, intermediate to peptidoglycan (PG), and high to LPS. Small, not significant increases in Ig responses to LPS (which occurred during the first 2 wks) were observed, whereas, the responses to PG, protein A, CW and PWM continued to increase for 8 wks, and the increases were high and significant. In most cases, there was no change in the dose response and kinetics patterns (characteristic for each stimulant) during ontogeny. Ontogenic development of autoantibody-secreting cells was different from the development of cells secreting all Ig and anti-SRBC antibodies. The increases in the numbers of cells secreting IgM anti-DNA and IgM anti-bromelin-treated mouse RBC antibodies in response to LPS and PG during postnatal development were larger than the increases of all IgM-secreting cells. In contrast, the increases of IgM anti-DNA secreting cells in response to protein A and PWM were smaller than the increases of all IgM-secreting cells. The frequencies of cells secreting anti-DNA antibodies in LPS- and PG-stimulated cultures were low in newborns and continued to increase until 8 wks of age, but they were high and did not change throughout ontogeny in protein A-stimulated cultures. Changes in the frequencies of anti-RBC antibody-secreting cells were less distinct and mostly insignificant. Postnatal changes in mitogenic responses were smaller and not correlated with the development of polyclonal Ig responses. Our data indicate different modes of ontogenic development of the ability of cells to produce polyclonal Ig, autoantibodies and heteroantibodies, and to synthesize DNA, in response to different stimulants.