Clinical significance of ossification of the cartilages of the front feet based on nuclear bone scintigraphy, radiography and lameness examinations in 21 Finnhorses

REASONS FOR PERFORMING STUDY

Research on the clinical significance of ossification of the cartilages of the foot has been limited, despite the common nature of the condition and conflicting reports in previous literature.

HYPOTHESIS

Some radiographic features in the ossification of the cartilages, such as incomplete fusion lines between separate centres of ossification and the ossified base, are of clinical significance.

METHODS

The relationships between radiopharmaceutical uptake in bone phase nuclear scintigraphy at the heels (palmar processes of the distal phalanx, including ossification of the cartilages of the foot), radiographic extent and type of ossification of the cartilages and clinical lameness were evaluated retrospectively in 21 Finnhorses (age > or = 4 years) in a total of 36 front feet.

RESULTS

No significant relationship between height of the ossifications and radiopharmaceutical uptake at the ipsilateral heels existed. Clearly separate centres of ossification were not associated with increased uptake. Moderately increased uptake was suspected to be associated with ossification of the adjacent cartilage in only one foot. Intense uptake was present unilaterally in 4 horses, at one medial and 3 lateral heels. In 2 of these horses, a unilateral palmar digital nerve block relieved the mild lameness; 2 horses had no obvious lameness but had a history of being stiff or having locomotion problems during high speed trot. At 2 of the lateral heels, an incomplete fusion line was present between a large separate centre of ossification and the base, and the third horse had a high sidebone with bony protrusions, suggestive of chronic entheseopathy in a narrow foot. At the medial heel, an oblique radiograph revealed a faint radiolucent line at the base of the ossification. In all cartilages with intense radiopharmaceutical uptake at the heel and/or lameness, the ossified part of the cartilage was wider and more irregular compared to other ossifications of the front feet of the individual.

CONCLUSIONS

Increased radiopharmaceutical uptake, associated with a different radiographic appearance from that of other ossifications of the front feet, was a conclusive sign of clinical significance. Obscure locomotion problems were more commonly associated with ossification of the cartilages than true lameness.

POTENTIAL RELEVANCE

This information is useful in lameness and prepurchase examinations and is likely also to be applicable to other coldblooded breeds used for athletic purposes.

Effect of Insemination Volume on Uterine Contractions and Inflammatory Response and on Elimination of Semen in the Mare Uterus - Scintigraphic and Ultrasonographic Studies

The effect of artificial insemination (AI) volume on uterine contractility and inflammation and on elimination of semen in the reproductive tract of mares was examined for 4 h after AI using two methods, scintigraphy and ultrasonography. The same doses were used in both methods: 2 and 100 ml of skim milk-extended frozen semen. In the scintigraphic study, the number of reproductively normal mares was four per group and in the ultrasonographic study five per group. For scintigraphy, the semen was radiolabelled with technetium-99m. The static scintigrams were acquired immediately before and 30, 60, 120, 180 and 240 min after AI. The activities in the vagina and uterus were calculated and the values for sperm that had been discharged from the mare were obtained by subtracting the counts for the uterus and vagina from the total radioactivity. The dynamic scintigrams were taken continuously for the first 30 min after AI and in 5-min periods immediately after having acquired the static scintigrams. The uterine contractions were counted. In the ultrasonographic study, the mares were scanned before AI and at 5, 10, 15, 20, 25, 30, 60, 120, 150, 180, and 240 min after AI, for at least 1 min each time. The examinations were videotaped and contractions counted per minute. More contractions were observed with the ultrasonographic method than with the scintigraphic method. No difference was present in the number of contractions between the groups, except in the ultrasonographic study at 4 h, when the mares inseminated with 100 ml showed more contractions than did the mares inseminated with 2 ml. The intraluminal fluid was sampled with a tampon and by uterine lavage 4 h after AI in the ultrasonographic study. The numbers of polymorphonuclear leukocytes and spermatozoa were counted, but the differences between the groups were not significant. Under our experimental conditions and with the number of mares examined, the volume of the AI dose had an insignificant effect on contractility - with the exception at 4 h - and inflammatory reaction and on semen elimination in the uterus.

Transport of spermatozoa in the reproductive tracts of mares

A scintigraphic method was developed to study sperm migration in the reproductive tracts of mares. Mares (n=5) and stallions (n=2) were used to test various steps of the procedure and three other mares and a stallion were used to study sperm transportation. A radiolabelling solution was prepared from 99mTc (Technetium-99m) and hexamethyl propylene amine oxime. The highest labelling of spermatozoa (57-72%) was obtained by incubation of the spermatozoa with the radiolabelling solution for 20 min at 20 degrees C. Radioactivity outside the spermatozoa was removed by centrifugation and by two subsequent washings with skimmed milk extender. The labelled spermatozoa were inseminated into the uterine bodies of detomidine-sedated mares undergoing oestrus and scintigraphic images were obtained for 4.5 h after insemination. Both dynamic (two pictures s(-1), 2 min multiple scans, 64 x 64 matrix) and static scans (20 s, 64 x 64 matrix) were used to image the mares. The attenuation of gamma radiation in the vagina and uterus was determined for each mare. Radioactive spermatozoa were found in the tips of the uterine horns for the first time at about 8-20 min after insemination. The frequency of uterine contractions varied considerably among mares and ranged from five to 65 contractions during the first 30 min after insemination. Within 1 h after insemination most of the sperm activity was in the uterus. At 2.5 h after insemination, most of the spermatozoa had left the uterus and were either in the vagina or had escaped into the vulva and been discharged. At 4.5 h after insemination there was hardly any sperm activity in the uterus and a small amount of activity only in the vagina; most spermatozoa had been eliminated from the mares.

Failure to demonstrate public idiotypes on cytolytic cells with specificity for NP-coupled syngeneic cells

We have investigated whether cytolytic cells specific for hapten-coupled syngeneic cells have the same public idiotype as serum antibodies against the same hapten, NP-aminocaproyl (NP-cap). Anti-NP-cap antibodies of C57BL mice possess a public idiotype that can be detected by antisera against the whole V region of the antibody molecule or against the VH domain. Neither reagent had an effect on the cytolytic response either when they were used to sensitize the effector cells for complement killing or when used at high concentrations in the culture medium during the secondary stimulation in vitro.

Allotype-associated differences in concentrations of human IgA2

Concentrations of immunoglobulin (Ig)A2 were determined in 176 Finnish blood donor sera. Their IgA, IgM, IgE, IgG1, IgG2, IgG3 and IgG4 concentrations and Gm allotypes had been determined earlier. The mean concentration of IgA2 was higher in individuals carrying the Gm(ax) allele (0.15 g/l) than in those negative for Gm(x) (0.103 g/l). The difference was statistically significant (P = 0.006). As > or = 70% of IgA was usually IgA1, its concentration could be calculated fairly reliably by subtracting the IgA2 value from the IgA value. The mean IgA1 concentration (2.03 g/l) seemed to be independent of the Gm allotypes.

Intrauterine fluid accumulation in oestrous mares

Intrauterine fluid (IUF) was collected using a tampon from mid-oestrous mares (n = 57) with and without ultrasonically detectable accumulations of free intraluminal fluid. Bacteria were cultured and neutrophils counted from all samples (n = 57). Total protein concentration, trypsin-inhibitor capacity (TIC), and plasmin, beta-glucuronidase (B-Gase) and N-acetyl-beta-D-glucosaminidase (NAGase) activities were determined in 27 IUF samples. The motility of spermatozoa in the presence of IUF, IUF extended with Kenney's medium (1:1) and Kenney's medium alone was analysed in 9 samples using a Hamilton-Thorn motility analyser. Thirty-five mares were inseminated immediately after collection of IUF, and every second day until ovulation. Embryos were recovered nonsurgically 6 days after ovulation. After embryo transfer, fluid accumulations were recorded during oestrus and an endometrial biopsy specimen taken (n = 53). In the beginning of oestrus, fluid accumulations were detected in 39% (22/57) of mares, while on the day when IUF was collected, fluid accumulations were observed in 26% (15/57) of mares. The fluid was anechogenic, and in 80% of the mares located in the uterine body. None of the mares exhibited cytological or bacteriological evidence of acute endometritis. Total protein concentrations, TIC and B-Gase activities in IUF were statistically significantly lower in mares with fluid accumulations (n = 14) than in mares without fluid accumulations (n = 13) (p < 0.01). The addition of undiluted IUF to extended semen significantly reduced total and progressive motilities, path velocities and percentages of rapid spermatozoa (p < 0.05) in vitro. On endometrial biopsy, fibrosis was found to be more prominent (p = 0.025) in mares with fluid accumulations (n = 9) than in mares without (n = 44). It was concluded that anechogenic fluid accumulations during oestrus were associated with compositional changes in IUF. Although IUF had negative effects on spermatozoal motility in vitro, the presence of fluid accumulations at the time of insemination did not affect embryo recovery rates.

Intrauterine fluid accumulation in oestrous mares

Intrauterine fluid (IUF) was collected using a tampon from mid-oestrous mares (n = 57) with and without ultrasonically detectable accumulations of free intraluminal fluid. Bacteria were cultured and neutrophils counted from all samples (n = 57). Total protein concentration, trypsin-inhibitor capacity (TIC), and plasmin, beta-glucuronidase (B-Gase) and N-acetyl-beta-D-glucosaminidase (NAGase) activities were determined in 27 IUF samples. The motility of spermatozoa in the presence of IUF, IUF extended with Kenney's medium (1:1) and Kenney's medium alone was analysed in 9 samples using a Hamilton-Thorn motility analyser. Thirty-five mares were inseminated immediately after collection of IUF, and every second day until ovulation. Embryos were recovered nonsurgically 6 days after ovulation. After embryo transfer, fluid accumulations were recorded during oestrus and an endometrial biopsy specimen taken (n = 53). In the beginning of oestrus, fluid accumulations were detected in 39% (22/57) of mares, while on the day when IUF was collected, fluid accumulations were observed in 26% (15/57) of mares. The fluid was anechogenic, and in 80% of the mares located in the uterine body. None of the mares exhibited cytological or bacteriological evidence of acute endometritis. Total protein concentrations, TIC and B-Gase activities in IUF were statistically significantly lower in mares with fluid accumulations (n = 14) than in mares without fluid accumulations (n = 13) (p < 0.01). The addition of undiluted IUF to extended semen significantly reduced total and progressive motilities, path velocities and percentages of rapid spermatozoa (p < 0.05) in vitro. On endometrial biopsy, fibrosis was found to be more prominent (p = 0.025) in mares with fluid accumulations (n = 9) than in mares without (n = 44). It was concluded that anechogenic fluid accumulations during oestrus were associated with compositional changes in IUF. Although IUF had negative effects on spermatozoal motility in vitro, the presence of fluid accumulations at the time of insemination did not affect embryo recovery rates.

Extensive allelic sequence variation in the J region of the human immunoglobulin heavy chain gene locus

During the initial stages of B lymphocyte differentiation heavy chain variable (VH), diversity (DH) and joining (JH) gene segments recombine to form a functional heavy chain variable region (VDJ) gene. Evidence for genetic polymorphism of the human JH gene segments has been obtained from mature rearranged VDJ sequences. We conducted an analysis of the published rearranged JH gene sequences and found that the JH alleles present in the two published germ-line JH region sequences were rare (approx. 2%) in the rearranged sequences. As an attempt to explain this discrepancy a 2.5-kb strech of DNA containing all the six heavy chain JH region genes and the most 3' DH gene segment, DHQ52, was amplified by the polymerase chain reaction from 39 individuals and analyzed for restriction fragment length polymorphism. Five new JH region haplotypes were found and sequenced. These new haplotypes contained the coding segment alleles that were frequent in antibody genes. Surprisingly, a high number of interallelic differencies in the non-coding sequence was found between the new and the two previously published haplotypes implying that the haplotypes had been separated early in evolution. In this respect the JH locus resembles HLA loci.

V-region-mediated binding of human Ig by protein A

The Fab-mediated "alternative" binding of Ig by staphylococcal protein A is a marker of a set of VH genes (a subset of family VH3 in man). We typed 115 monoclonal human Ig as alternative binders or nonbinders. The proportion of binders varied depending on the isotype, 35% in IgM but only 11-13% in IgA1 and IgG3. It was 28% among lambda-chain-bearing but 16% among kappa-bearing monoclonal Ig. Independent estimates of the proportions bound were obtained by studying polyclonal Ig of 10 healthy adults. The proportions bound were close to those observed in the study of monoclonal Ig (the means were IgM 32%, IgA1 13%, IgA2 24%, IgG3 14%). A higher proportion of infant than adult Ig was bound by protein A. Also, the proportion was less isotype-dependent in infants than in adults. At the age of 4 mo, 47% of IgM was bound (mean of 10 children), the values of other isotypes were: IgA1 35%, IgA2 39%, and IgG3 38%. At the age of 14 mo the proportion of alternative binders had decreased but was still far from adult values. We propose that ontogenically early ("virgin") B cells, besides being rich in IgM and lambda-chain producers, are rich in producers of alternative binders. A subsequent selection reduces the proportion of these B cells so that in ontogenically most developed B cell populations, e.g., those producing IgA1 kappa, such cells make up only about 10% of the total.

V-region-mediated binding of human Ig by protein A

The Fab-mediated "alternative" binding of Ig by staphylococcal protein A is a marker of a set of VH genes (a subset of family VH3 in man). We typed 115 monoclonal human Ig as alternative binders or nonbinders. The proportion of binders varied depending on the isotype, 35% in IgM but only 11-13% in IgA1 and IgG3. It was 28% among lambda-chain-bearing but 16% among kappa-bearing monoclonal Ig. Independent estimates of the proportions bound were obtained by studying polyclonal Ig of 10 healthy adults. The proportions bound were close to those observed in the study of monoclonal Ig (the means were IgM 32%, IgA1 13%, IgA2 24%, IgG3 14%). A higher proportion of infant than adult Ig was bound by protein A. Also, the proportion was less isotype-dependent in infants than in adults. At the age of 4 mo, 47% of IgM was bound (mean of 10 children), the values of other isotypes were: IgA1 35%, IgA2 39%, and IgG3 38%. At the age of 14 mo the proportion of alternative binders had decreased but was still far from adult values. We propose that ontogenically early ("virgin") B cells, besides being rich in IgM and lambda-chain producers, are rich in producers of alternative binders. A subsequent selection reduces the proportion of these B cells so that in ontogenically most developed B cell populations, e.g., those producing IgA1 kappa, such cells make up only about 10% of the total.

Low concentrations of Gm allotypic subsets G3 mg and G1 mf in homozygotes and heterozygotes

Serum concentrations of IgG3, IgG1, and of the Gm allotypic subsets of these two isotypes were measured in adult homozygotes and heterozygotes. Alleles G3 mb and G3 mst of the IgG3 locus, and alleles G1 ma and G1 max of the IgG1 locus were found to associate with a high concentration of the allotypic product. Alleles G3 mg (IgG3) and G1 mf (IgG1) were associated with a low concentration of the product. This was true regardless of the haplotype; for example, allele G3 mb was associated with a high concentration of the product in all haplotypes f;n+;b f;n-;b and fa;n+;b. One dose of allele G3 mg was associated with a characteristic mean concentration of the product (g-type IgG3). This rule was valid regardless of the other allele of the subject, thus, heterozygotes and G3 mg/g homozygotes had mean concentrations of 0.10 and 0.20 g/liter, respectively, of g-type IgG3. Products of the IgG1 alleles were also simply additive: one dose of allele G1 ma(x) or G1 mf was associated with mean concentrations of 3.63 and 2.84 g/liter, respectively, and two doses with twice these amounts. Only allele G3 mb did not completely follow this rule. We also studied the serum concentrations and the allotype distribution of 41 IgG1 and 31 IgG3 myeloma proteins. The results suggested that the allotype-associated differences in serum concentrations are caused by different numbers of B cells producing allotypic subsets of IgG1 or IgG3, not by different rates of synthesis per B cell.

Proportion of protein A bindable molecules in human IgM and IgA antibodies to seven antigens

Human IgM or IgA antibodies to seven antigens (tetanus and diphtheria toxoids, and five bacterial polysaccharides) were studied by determining what proportion of these antibodies were bound by staphylococcal protein A. This alternative binding is a marker of VH genes of family 3. Each response was studied in an average of nine individuals. The binding proportion of antibodies to the two toxoids resembled that of total serum immunoglobulins; 13-14% of IgA and 40% of IgM antibodies were bound by protein A. All anti-polysaccharide antibodies had higher proportions of protein A bindable molecules than serum IgM or IgA indicating a bias for VH genes. This excess was high in antibodies to Haemophilus influenzae type b (Hib) and pneumococcal type 14 polysaccharides (> two-fold). It was moderate but statistically significant in antibodies to pneumococcal types 18C and 3 capsular polysaccharides and to C polysaccharide. All vaccinated Finns exhibited the VH3-preference in antibodies to Hib and type 14 polysaccharide.

Low concentrations of Gm allotypic subsets G3 mg and G1 mf in homozygotes and heterozygotes

Serum concentrations of IgG3, IgG1, and of the Gm allotypic subsets of these two isotypes were measured in adult homozygotes and heterozygotes. Alleles G3 mb and G3 mst of the IgG3 locus, and alleles G1 ma and G1 max of the IgG1 locus were found to associate with a high concentration of the allotypic product. Alleles G3 mg (IgG3) and G1 mf (IgG1) were associated with a low concentration of the product. This was true regardless of the haplotype; for example, allele G3 mb was associated with a high concentration of the product in all haplotypes f;n+;b f;n-;b and fa;n+;b. One dose of allele G3 mg was associated with a characteristic mean concentration of the product (g-type IgG3). This rule was valid regardless of the other allele of the subject, thus, heterozygotes and G3 mg/g homozygotes had mean concentrations of 0.10 and 0.20 g/liter, respectively, of g-type IgG3. Products of the IgG1 alleles were also simply additive: one dose of allele G1 ma(x) or G1 mf was associated with mean concentrations of 3.63 and 2.84 g/liter, respectively, and two doses with twice these amounts. Only allele G3 mb did not completely follow this rule. We also studied the serum concentrations and the allotype distribution of 41 IgG1 and 31 IgG3 myeloma proteins. The results suggested that the allotype-associated differences in serum concentrations are caused by different numbers of B cells producing allotypic subsets of IgG1 or IgG3, not by different rates of synthesis per B cell.

Half-life of the maternal IgG1 allotype in infants

The residence time of maternal IgG1 in the circulation of infants was measured by monitoring f-allotypic IgG1 or f-positive tetanus toxoid antibody in genetically G1mf-negative infants. G1ma-positive maternal tetanus toxoid antibody was similarly monitored in genetically a-negative infants. Blood samples were taken from infants at the age of 1-3 days, ca. 4 months, and ca. 6 months. An exponential decay at the same rate took place from age 1-3 days to 4 months and for the 2 subsequent months. The average concentration of the maternal IgG1 had dropped to ca. 10% of the 1- to 3-day value in 4 months and to ca. 3% in 6 months. The drop was due mainly to clearance but partly also to the weight increase of the child (doubling in 6 months). By correcting for the weight increase, we calculated that ca. 17 and 7% of the original maternal IgG1 was still present at ages 4 and 6 months, respectively. The average half-life of the maternal IgG1 was thus 48.4 days. The concentration of endogenous IgG1 in the cord blood was determined by studying a separate series of mother-newborn pairs. Assuming that cross-reactions of antiallotype reagents had no effect, the highest measured concentration of f-positive IgG1 in infants of f-negative mothers was 10 mg/L, half a percent of adult heterozygote values. Crossreaction may have played a role, however, and the value must be considered the upper limit of the true concentration.

The alternative binding site for protein A in the Fab fragment of immunoglobulins

Twenty-six new human or murine monoclonal immunoglobulins (IgM, IgA, murine IgG1 or human IgG3) with a known V-region sequence were tested for alternative (non-Fc) binding to Staphylococcal protein A. Seven of them did not bind at all. Four immunoglobulins (all mouse IgG1) were bound but easily eluted (at pH 6). They were probably bound via the Fc part. All eleven were classified as negative for alternative binding. Fifteen immunoglobulins were found to bind more firmly; they came off the protein A column at pH 4-3 (alternative binders). Amino acid sequences of immunoglobulins that have been typed in the present work or earlier (25 binders and 26 non-binders) were compared. The light chain, the C region of the heavy chain and the D and JH segments look irrelevant for alternative binding. The N-terminal portion (amino acids 1-94) of the H chain probably forms the ligand of protein A. A peptide making the ligand cannot be reliably localized within this stretch but binder proteins had a high homology in residues 6-29. All mouse immunoglobulins expressing VH genes of families J606 or S107 were alternative binders; those expressing other families were non-binders.

The same few V genes account for a majority of oxazolone antibodies in most mouse strains

The early primary anti-phenyloxazolone antibodies of 12 mouse strains were studied by determining proportions of two defined subsets id495 (the classical phOx idiotype) and id350. Id495-positive antibodies bear an H chain encoded by VHOx1 gene (family Q52) and an L chain usually coded for by VKOx1 but occasionally by other VK genes. Id350-positive antibodies are encoded by a VK gene VK45.1, and usually by a VH gene of the S107 family. All 12 strains (representing nine H-chain and four kappa-chain haplotypes) produced id350-positive anti-phOx antibodies. While id495 is the predominant major subset in the BALB/c response (originally studied), id350 seems to be the predominant subset of early anti-phOx antibodies in the mouse species. The combined proportion of the two subsets varied from ca. 50 to almost 100% of the total in all strains except C57BL.

Quantitation of human IgG subclass antibodies to Haemophilus influenzae type b capsular polysaccharide. Results of an international collaborative study using enzyme immunoassay methodology

An international collaborative study was conducted at ten sites to examine the performance of enzyme immunoassays (EIAs) for the quantitation of IgG1, IgG2, IgG3, IgG4 and total IgG anti-Haemophilus influenzae type b (Hib) capsular polysaccharide in human serum. All groups used the same reagents: microtiter plates coated with polyribosylribitol phosphate (PRP) conjugated to poly-L-lysine (PLL), reference, control and test human sera, biotin-conjugated International Union of Immunological Societies (IUIS)-documented monoclonal anti-human IgG1-4 and IgG Pan detection antibodies, avidin-peroxidase and TMB substrate. Initial mixing of soluble PRP antigen or an equal volume of buffer with the 20 test sera prior to analysis confirmed PRP antigen specificity in all five EIAs with greater than 80% competitive inhibition at most sites. Positive correlation between the total IgG anti-Hib and sum of IgG1-4 anti-Hib was demonstrated (r2 = 0.99, Y = 1.13X -0.15). Good agreement was shown between the total IgG anti-Hib as measured by EIA and the total Hib-specific antibodies measured by the current radiolabeled antigen binding assay (r2 = 0.97, Y = 4.6X -5.8). Assay parallelism was demonstrated with an average interdilutional %CV of 22% and parallel dose-response curve slopes. The interdilutional %CVs were calculated as an average per sample of the variation of microgram/ml (corrected for dilution) at different dilutions per laboratory for all participating sites. The interlaboratory variation was the only performance parameter studied that exceeded the target level of 35% CV in all IgG1-4 and total IgG anti-Hib assays. IgG subclass distributions in the test sera demonstrated a predominance of IgG1 anti-Hib in the pediatric serum pools and IgG2 anti-Hib in the adult sera, with low but detectable levels of IgG3 and IgG4 anti-Hib in each group.

V genes of oxazolone antibodies in 10 strains of mice

One pair of V genes (V kappa 45.1 and V11) code for a great portion of phenyloxazolone (anti-phOx) antibodies in 10 strains of mice. This combination replaces the first-known major combination VHOx1-V kappa Ox1 in some strains, and is important in most strains. C57BL/10 and SJL mice have an additional subset of antibodies encoded by genes V kappa 45.1 and V13 (a relative of V11). All three genes involved (V kappa 45.1, V11 and V13) have "allelic" variation. Four alleles of V11 were found, one in Igh haplotypes a, c and g, the second in haplotypes d, j and n, the third in b, and the fourth in f. The most distant alleles d, j, n and f had 10 nucleotide differences out of 429 determined (97.7% homology). Only one allele of the V13 gene was found from anti-phOx hybridomas but two others have been published. Three alleles of the V kappa 45.1 gene were found; one in NZB mice (Ig kappa haplotype b) another in CE (haplotype f), and the third in eight strains including representatives of three Ig kappa haplotypes (a, c and e). The three alleles had greater than 99.0% homology. The V11 and V13 genes that code for anti-phOx antibodies in C57BL/10 and SJL mice were different from the related genes found from the C57BL/10 germ line. C57BL/10 mice must have a chromosome bearing two V11 and two V13 genes. RF mice were found to have two V11 genes, and both code for anti-phOx antibodies. Our data show that the majority of antibodies in the anti-phOx response are encoded by the same restricted collection of V genes in most mouse strains. Antibody responses appear to be no less heritable than other functions of the body.

Gm allotypes influence the production of IgG3 but the effect is age-dependent

Serum concentrations of IgG3 were found to be higher in Gm-f-positive (= b-positive) than in f-negative individuals except in young children. Young children aged 3-4 months had a mean concentration of 0.24 g/l of IgG3 regardless of allotype. The concentration gradually rose with age in f-positive individuals to a geometric mean of 0.56 g/l in adults but it remained essentially unchanged in f-negative people. A corresponding allotype effect was seen in influenza-specific antibody responses. While the total IgG response (mainly IgG1) was equally strong in f-positive and in f-negative patients, f-positive (= b-positive) patients produced more IgG3 antibodies than f-negative patients. The difference between geometric mean values of opposite homozygotes (f/f versus f-negative) was 2.3-fold (p = 0.0113). This finding indicates that the b-positive gamma-3 allele is more productive than the g-positive allele.

Allotype-associated differences in concentrations of human IgG subclasses

The concentrations of seven immunoglobulin isotypes (IgA, IgE, IgM, IgG1, IgG2, IgG3, and IgG4) were measured in the sera of 207 Finnish blood donors, and they were allotyped with anti-Gm antibodies: anti-f, anti-a, anti-x, and anti-n. The above population could be divided into 12 phenotypes, and significant differences in isotype concentrations between different phenotypes were observed. They are best explained by postulating that the following alleles of different loci are associated with a high concentration of the product of the locus: a(x)-IgG1, n-IgG2, b-IgG3, and perhaps 4b-IgG4. The following concentration differences between the low and the high homozygotes were found: IgG1, 1.2-fold; IgG2, 1.5-fold; and IgG3, 2.6-fold. No significant allotype-associated differences in the concentrations of IgA, IgM, or IgE could be detected.

Mouse Ig coded by VH families S107 or J606 bind to protein A

Twenty-five monoclonal mouse Ig (5 IgA, 7 IgM, and 13 IgG1) were tested for binding to staphylococcal protein A. They were allowed to attach to protein A Sepharose column at pH 8.0 and were then eluted with a pH gradient from approximately 7.5 to 3.0. Five of them (IgM or IgA) did not bind. Ten came off with pH approximately 6. They were all IgG1, and were probably bound (weakly) via the Fc portion. The remaining 10 (3 IgA, 4 IgM, and 3 IgG1) were more firmly bound; they came off with pH-values ranging from 5.0 to 3.5. They all expressed VH genes of families J606 or S107, whereas all the 15 Ig that were not firmly bound expressed VH genes of six other families. The VL domains seem to be unimportant for protein A binding inasmuch as a firmly binding and a weakly binding IgG1 antibody share identical VK domains. VH sequences of protein A-binding and nonbinding Ig were compared. No likely peptide sequences were found that might make the ligand for protein A.

Mouse Ig coded by VH families S107 or J606 bind to protein A

Twenty-five monoclonal mouse Ig (5 IgA, 7 IgM, and 13 IgG1) were tested for binding to staphylococcal protein A. They were allowed to attach to protein A Sepharose column at pH 8.0 and were then eluted with a pH gradient from approximately 7.5 to 3.0. Five of them (IgM or IgA) did not bind. Ten came off with pH approximately 6. They were all IgG1, and were probably bound (weakly) via the Fc portion. The remaining 10 (3 IgA, 4 IgM, and 3 IgG1) were more firmly bound; they came off with pH-values ranging from 5.0 to 3.5. They all expressed VH genes of families J606 or S107, whereas all the 15 Ig that were not firmly bound expressed VH genes of six other families. The VL domains seem to be unimportant for protein A binding inasmuch as a firmly binding and a weakly binding IgG1 antibody share identical VK domains. VH sequences of protein A-binding and nonbinding Ig were compared. No likely peptide sequences were found that might make the ligand for protein A.

Effect of Gm allotypes on IgG2 antibody responses and IgG2 concentrations in children and adults

Earlier studies have suggested that in adults the n-positive allele of the human IgG2 gene is more productive than the n-negative allele. This superiority was seen to be manifested in IgG2 antibody responses to polysaccharides, in the higher serum concentration of total IgG2 in the n/n than in -/- individuals, and in the higher concentration of n-positive than n-negative IgG2 in heterozygotes. The present study shows that in 1- or 2-year-old children, the concentration of IgG2 was independent of allotype G2m(n), and both alleles of a heterozygote contributed an average of one-half of the total IgG2. On the other hand, the superiority of the n-positive allele was also seen in young children in IgG2 antibody responses induced by the Haemophilus influenzae type b polysaccharide (Hib). The effect of allotype n on antibody responses was evident only when the immunogen was the Hib polysaccharide. When the immunogen was a conjugate of Hib and diphtheria toxoid, the IgG2 antibody responses of n-positive and n-negative vaccinated individuals were almost equal, both in adults and in children.

Antigenicity of dextran-protein conjugates in mice. Effect of molecular weight of the carbohydrate and comparison of two modes of coupling

Protein conjugates of polysaccharides or their breakdown products are being used as improved "T-dependent" vaccines. We tried to define optimal characteristics of future conjugate vaccines by testing the immunogenicity of thirteen conjugates of alpha 1-6 dextran and chicken serum albumin in mice (BALB/c and CBA). All conjugates induced stronger antidextran antibody responses than the polysaccharide, and a fair proportion of these antibodies were IgG. However, there was a range of antigenicities. Consistently strong responses were obtained with conjugates that carried small dextran molecules (m.w. 1000 to 4000) coupled to the protein via the reducing end. Modification of such an "optimal" conjugate either by increasing the size of the saccharide to 40,000 Da, or by permitting multiple attachments of the saccharide molecule to the protein, reduced its antigenicity. Carbohydrate/protein ratios varying from 0.17 to 0.49 were associated with excellent antidextran responses.

Antigenicity of dextran-protein conjugates in mice. Effect of molecular weight of the carbohydrate and comparison of two modes of coupling

Protein conjugates of polysaccharides or their breakdown products are being used as improved "T-dependent" vaccines. We tried to define optimal characteristics of future conjugate vaccines by testing the immunogenicity of thirteen conjugates of alpha 1-6 dextran and chicken serum albumin in mice (BALB/c and CBA). All conjugates induced stronger antidextran antibody responses than the polysaccharide, and a fair proportion of these antibodies were IgG. However, there was a range of antigenicities. Consistently strong responses were obtained with conjugates that carried small dextran molecules (m.w. 1000 to 4000) coupled to the protein via the reducing end. Modification of such an "optimal" conjugate either by increasing the size of the saccharide to 40,000 Da, or by permitting multiple attachments of the saccharide molecule to the protein, reduced its antigenicity. Carbohydrate/protein ratios varying from 0.17 to 0.49 were associated with excellent antidextran responses.

‘Allelic’ forms of immunoglobulin V genes in different strains of mice

A VH gene (Ox1) has a major role in the early antibody response of several mouse strains to hapten phenyloxazolone (phOx). Antibodies that are coded by this gene are positive for idiotype 495. Idiotype-positive monoclonal antibodies originating from the early primary response of nine strains were partially sequenced (mRNA). All 21 antibodies were coded by this gene, most of them also by one VL gene, VKOx1(H3). Very few somatic mutations were found, and the germ-line sequence of the two genes in several strains can be predicted. Four 'alleles' of the VHOx1 gene have 99-99.7% sequence homology to each other. One allele was found in Igh allotype j strains CBA and C3H, another in allotype c strains DBA/2 and RF, the third in allotype f strain CE and the fourth in BALB/c, 129, A/J and RIII mice (allotypes a, e or g). The VKOx1(H3) gene has the same sequence in eight strains. RF mice do not use this gene for the anti-phOx response. Our data suggest that antibody responses are inherited to a considerable extent and that immunoglobulin V genes are as stable as other genes in evolution.

One allele [G2m(n)] of the human IgG2 locus is more productive than the other

Earlier investigators have shown that a high serum concentration of IgG2 and a high IgG2 antibody response to several polysaccharide antigens is associated with the allotype G2m(n) of the IgG2 subclass. We now show that the total IgG2 concentrations are significantly higher in G2m(n) than in G2m(-n) homozygotes (difference of means was 1.26-fold, p = 0.002). Furthermore, in G2m(n) heterozygotes, the G2m(n) allele contributed more than the G2m(-n) allele to specific IgG2 antibody responses and to the total IgG2.

Antibody responses to hapten in thymectomized mice: extraordinarily pronounced deficiency in IgG1 production

The effect of thymectomy on the production of antibodies was studied by immunizing mice with hapten-carrier conjugates. Antibody responses were analysed with monoclonal antibody-based quantitative isotype-resolving assays. In spite of bone marrow reconstitution, irradiation without thymectomy caused a long-lasting relative deficiency in responsiveness to T-independent antigens. Even when no visible remnants of the thymus could be observed at the autopsy of thymectomized mice, there appeared to be a gradual recovery of antibody-forming capacity within 4 months, as assessed by the response to a T-dependent antigen. Therefore, some of the thymectomized mice had to be regarded as having recovered with respect to the helper T-cell effect. The antibody responses to T-dependent antigens were improved in all isotypes by a functional T-cell system, but the IgG isotypes seemed to benefit more than IgM. The most conspicuous deficit in antibody production in non-recovered thymectomized mice was observed in the T-dependent responses of the IgG1 isotype (2000-fold reduction in contrast to about 50- to 100-fold in IgG2a, IgG2b, and IgG3).

Recent primary toxoplasma infection indicated by a low avidity of specific IgG

An unusual assay was developed for the serologic diagnosis of recent primary infection by Toxoplasma gondii. This test measures the antigen-binding avidity of toxoplasma-specific IgG antibodies. Serum samples from 5 patients with recent primary toxoplasma infection were compared with those from 21 subjects with preexisting toxoplasma immunity. Patients with primary infection exhibited a low avidity of toxoplasma-specific IgG, which persisted for several months after the onset of symptoms of toxoplasmosis. In contrast, all subjects with past immunity had a high avidity of toxoplasma-IgG. This IgG avidity assay should assist in the diagnosis of acquired toxoplasmosis and may be used to identify pregnancies that are at risk for congenital toxoplasmosis.

IgG subclasses of pneumococcal antibodies--effect of allotype G2m(n)

Antibody responses to three pneumococcal polysaccharides (types 3, 14, and 18C) were analysed after vaccination with a 23-valent polysaccharide vaccine. Antibodies to all three polysaccharides could be detected before immunization. Clear cut IgG, IgA, and/or IgM antibody responses to the polysaccharides were seen in three-quarters of the vaccinees. IgG2 was the predominant and IgG1 the second most abundant subclass of anti-pneumococcal IgG antibodies both before and after the vaccination. The relative proportions of IgG2 and IgG1 antibodies exhibited a continuous variation from 1:0 to approximately 0:2. After vaccination, G2m(n)-positive homozygotes had about four times more IgG2 antibodies (anti-14 and anti-18C) than G2m(n)-negative vaccinees. Heterozygotes occupied an intermediate position. The same pattern was seen less clearly in type 3 antibodies after vaccination, and in all three antibodies before vaccination. The G2m(n) allotypes had no detectable effect on the levels of IgG1, IgG4, or IgM antibodies, and possibly a weak effect on IgG3 and IgA antibodies (G2m(n)-positive homozygotes responded strongly).

Isotype distribution and bactericidal activity of antibodies after immunization with Haemophilus influenzae type b vaccines at 18-24 months of age

The serum antibody response to Haemophilus influenzae type b capsular polysaccharide or its protein conjugate vaccine (PRP and PRP-D, respectively) was studied in 28 children initially immunized at the age of 24 mo with either vaccine and in 10 children immunized for the third time with PRP-D at the age of 18 mo. The methods used were isotype-resolving enzyme immunoassay, Farr-type radioimmunoassay, and the in vitro bactericidal activity (BCA) test. Immunization with PRP evoked a higher proportion of IgA antibodies than did either the first or third dose of PRP-D, whereas the latter vaccine evoked a somewhat higher IgG response, but the differences were not statistically significant. In all groups the IgG antibody responses were predominantly IgG1, with the mean proportions being 82.2%, 84.2%, and 65.9% in the PRP, first-dose PRP-D, and third-dose PRP-D groups, respectively. Postimmunization antibodies were functionally active in the BCA test.

Human antibody responses to two conjugate vaccines of Haemophilus influenzae type B saccharides and diphtheria toxin

Antigenicity of two Haemophilus influenzae type b (Hib) conjugate vaccines was studied by immunizing adults and 2-year-old children. Both vaccines induced strong anti-Hib responses and strong antibody responses to diphtheria toxin (DT), the protein part of the conjugate. The adults' responses were stronger than the children's. A conjugate of Hib oligosaccharide and mutant diphtheria toxin (HbOC) emerged as slightly superior to a conjugate of Hib polysaccharide and diphtheria toxoid (PRP-D). HbOC induced somewhat higher total anti-Hib responses and significantly higher IgG1 anti-Hib responses than PRP-D. IgG1 and IgG2 were the main IgG subclasses of the anti-Hib antibodies, whereas IgG1 and IgG4 were the main subclasses of the anti-DT antibodies. Within this main rule, the ratio IgG1/IgG2 of anti-Hib antibodies varied between individuals. The average ratio was higher than five in children but approximately one in adults. It was lower in adult recipients of the polysaccharide conjugate (0.69) than in adult recipients of the oligosaccharide conjugate (1.55). A large interindividual variation was observed in concentrations of IgG2 of Hib specificity, perhaps reflecting a small number of IgG2-committed B-cell clones participating in the response.

Genetic control of early antibody responses

By using a pair of strains that have similar VK haplotypes but different VH haplotypes (e.g. BALB/c and C57BL) it is possible to demonstrate VH-controlled genetic differences in antibodies. By using a pair that have similar VH haplotypes but different VK haplotypes (RF and BALB/c) it is possible to demonstrate VK-controlled genetic differences in antibodies. A plausible explanation for the high frequency of certain V-gene combinations in the primary response is a high affinity of the product without somatic mutations. The products of two such major primary response combinations (VHOx1/VKOX1(H3) and VH186.2/V lambda 1) have an affinity for the immunogen well above 10(6). One combination of V genes, VHOx1/VKOx1(H3) has a major role in the primary anti-phOx response of several mouse strains - the product is idiotype 260. C57BL/10 mice lack the VHOx1 and RF mice the VKOx1(H3) gene. They use the remaining partner of the pair for the response in combination with other genes, but the affinity of the product is lower than the affinity of id. 260. Concordantly, the frequency of these "half-idiotypes" is lower in the primary response than the frequency of the full combination (23% and 16% instead of 50%). When the product of a V-gene combination is very frequent in the primary response, the affinity for the immunogen must be high, but the reverse is not always true. The product of a combination can have an unusually high affinity but the frequency is low. The simplest explanation then is that the frequency of available virgin B cells is low. It can be low because of a low rearrangement frequency of one of the V genes, VH or VK. Another possibility is that only a small proportion of B cells that have the particular combination rearranged can be recruited to the response. We have discussed an example where strict heavy chain CDR3 requirements must strongly limit available B cells.

Combinatorial association of V genes: one VH gene codes for three non-cross-reactive monoclonal antibodies each specific for a different antigen (phoxazolone, NP or gat)

Two anti-phenyloxazolone (phOx3) and one anti-GAT MAbs from C57BL mice are shown to be coded by VH gene 186.2. This gene has been found earlier to code for several anti-NP (NNP) antibodies (Bothwell et al., 1981) and anti-GT antibodies (Rocca-Serra et al., 1983; Carmack and Pincus, 1986). The L chain partner of the VH 186.2 gene is different in anti-NP and anti-GAT antibodies (Bothwell et al., 1981; Rocca-Serra et al., 1983; Carmack and Pincus, 1986); in anti-phOx antibodies two new unrelated kappa chain V regions were found. Both of the new VK genes involved code frequently for anti-phOx antibodies in BALB/c mice but then with different VH genes. We tested five 186.2-coded antibodies for cross-reactions. Four antibodies were specific, one bound only to NNP, one only to phOx and two only to GT (GAT). The fifth antibody (anti-phOx) bound also to NNP, GAT and ABA-HOP though probably with a low affinity. This is the first demonstration that one V gene can code for three different antibody specificities. It emphasizes the role of the combinatorial element in antibody diversity.

V genes of the primary antibody response of C57BL/10 mice to the hapten phenyloxazolone

The mRNA of ten monoclonal phenyloxazolone (phOx) antibodies originating from the primary (day 7) response of C57BL/10 mice were partially sequenced. The sequences were analyzed together with those of two previously published antibodies. The C57BL response does not have a predominant subset of antibodies like the BALB/c response has (VH-Ox1/V kappa-Ox1 JK5). Probably, C57BL mice lack the VH-Ox1 gene and, as a consequence, their V kappa-Ox1 gene does not have a main role in the anti-phOx response. Five V kappa and six VH genes were found to participate. All five V kappa genes or their "alleles" had previously been found from the BALB/c response to 2-phenyloxazolone (phOx). On the other hand, the two strains use different VH genes for the anti-phOx response. Most C57BL antibodies were coded by VH genes of group 1 which has only minor role in the BALB/c response. The remaining VH genes were from group 7. Our data show that one V kappa segment (e.g. V kappa-Ox1) can code for anti-phOx antibodies with several, even widely different, VH genes. On the other hand, they emphasize the role of certain VH/VL gene combinations for the anti-phOx specificity. Thus, VH genes of group 7 were found to code for anti-phOx antibodies only together with the V kappa 45.1 gene.

Isotype concentrations of human antibodies to Haemophilus influenzae type b polysaccharide (Hib) in young adults immunized with the polysaccharide as such or conjugated to a protein (diphtheria toxoid)

Antibody responses of young adults to Haemophilus influenzae type b polysaccharide (Hib) or its protein conjugate were studied with special attention to the isotype composition of the antibodies. Three conclusions of interest can be made: 1) Immunoglobulin G (IgG) antibodies in polysaccharide-immunized volunteers displayed the subclass pattern previously found in antibodies to meningococcal type A polysaccharide. IgG1 was the predominant subclass in IgG antibodies of some individuals, IgG2 in others. Still others had the two subclasses in varying but more even proportions. 2) The conjugate vaccine induced a geometric mean response 2 to 3 times higher and an IgG response 4 times higher to Hib than the polysaccharide vaccine. 3) Anti-Hib antibodies induced by the conjugate vaccine still had essentially the same IgG subclass composition as anti-Hib antibodies induced by the polysaccharide. This composition was strikingly different from the composition of the anti-diphtheria toxoid response induced by the same conjugate vaccine.

Isotype concentrations of human antibodies to Haemophilus influenzae type b polysaccharide (Hib) in young adults immunized with the polysaccharide as such or conjugated to a protein (diphtheria toxoid)

Antibody responses of young adults to Haemophilus influenzae type b polysaccharide (Hib) or its protein conjugate were studied with special attention to the isotype composition of the antibodies. Three conclusions of interest can be made: 1) Immunoglobulin G (IgG) antibodies in polysaccharide-immunized volunteers displayed the subclass pattern previously found in antibodies to meningococcal type A polysaccharide. IgG1 was the predominant subclass in IgG antibodies of some individuals, IgG2 in others. Still others had the two subclasses in varying but more even proportions. 2) The conjugate vaccine induced a geometric mean response 2 to 3 times higher and an IgG response 4 times higher to Hib than the polysaccharide vaccine. 3) Anti-Hib antibodies induced by the conjugate vaccine still had essentially the same IgG subclass composition as anti-Hib antibodies induced by the polysaccharide. This composition was strikingly different from the composition of the anti-diphtheria toxoid response induced by the same conjugate vaccine.

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 fluid (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.

Functional analogues of the VKOx1 gene in different strains of mice: evolutionary conservation but diversity based on V-J joining

Monoclonal antibodies to the hapten phenyloxazolone were raised 7 days after immunization in mice of six strains (BALB/c, C57BL-Igha, DBA2, RF, A/J, and CE). Hybridomas were selected that produced 260 idiotype-positive antibodies, and their light chain mRNA were partially sequenced. (RF is an idiotype-negative strain, and sequencing was done without this selection.) All newly sequenced BALB/c, C57BL-Igha, DBA/2, A/J, or CE VK segments had a 100% nucleotide homology with the VKOx1 (H3) germline gene. This gene codes for one third of early BALB/c phenyloxazolone antibodies, and according to our results the same gene has a significant role in the early response of at least five strains of mice. Four RF hybridomas had identical nucleotide sequences, suggesting that they express a non-mutated nucleotide sequence of a new VK germ-line gene (VKOx2). This gene codes for a CDR1 which is two amino acids longer than the CDR1 coded by the VKOx1 gene, but otherwise the two genes are related (94.5% sequence homology). All but one of the 16 kappa chains studied had the J5 segment; this segment had the same sequence in all six strains. One RF antibody had the J4 segment the nucleotide sequence of which differs from the BALB/c J4 segment in two places. Three of the kappa chains had an extra long CDR3. Long and "normal" kappa chains were probably coded by the same pair of germ-line genes (VKOx1 and J5, or VKOx2 and J5). The length heterogeneity was probably caused by a lack of precision in VK-JK joining.

Functional analogues of the VKOx1 gene in different strains of mice: evolutionary conservation but diversity based on V-J joining

Monoclonal antibodies to the hapten phenyloxazolone were raised 7 days after immunization in mice of six strains (BALB/c, C57BL-Igha, DBA2, RF, A/J, and CE). Hybridomas were selected that produced 260 idiotype-positive antibodies, and their light chain mRNA were partially sequenced. (RF is an idiotype-negative strain, and sequencing was done without this selection.) All newly sequenced BALB/c, C57BL-Igha, DBA/2, A/J, or CE VK segments had a 100% nucleotide homology with the VKOx1 (H3) germline gene. This gene codes for one third of early BALB/c phenyloxazolone antibodies, and according to our results the same gene has a significant role in the early response of at least five strains of mice. Four RF hybridomas had identical nucleotide sequences, suggesting that they express a non-mutated nucleotide sequence of a new VK germ-line gene (VKOx2). This gene codes for a CDR1 which is two amino acids longer than the CDR1 coded by the VKOx1 gene, but otherwise the two genes are related (94.5% sequence homology). All but one of the 16 kappa chains studied had the J5 segment; this segment had the same sequence in all six strains. One RF antibody had the J4 segment the nucleotide sequence of which differs from the BALB/c J4 segment in two places. Three of the kappa chains had an extra long CDR3. Long and "normal" kappa chains were probably coded by the same pair of germ-line genes (VKOx1 and J5, or VKOx2 and J5). The length heterogeneity was probably caused by a lack of precision in VK-JK joining.

Salivary and serum antibodies in patients with Yersinia enterocolitica infection

The systemic and secretory antibody response in patients with yersiniosis was studied by measuring Yersinia antibodies of various isotypes (IgG, IgA and IgM) and the total concentrations of the corresponding Ig classes in serum and saliva. Specific antibody activities of IgG (IgG antibody concentration divided by IgG concentration) were almost identical in serum and saliva of all patients although the pair of values varied from patient to patient. Almost all salivary IgG of these patients was therefore probably a transudate from the blood. Specific antibody activities of IgA and of IgM, on the other hand, varied independently in serum and saliva. Occasional great differences between serum and saliva values indicate that most of the salivary IgA and IgM (more than 90%) is produced locally at least in some individuals. The local anti-Yersinia response was restricted to IgA in some individuals, to IgM in others, whilst yet other patients produced salivary antibodies of both isotypes.

Proportions of IgG subclasses in antibodies formed during vaccination with hepatitis B surface antigen

Nineteen healthy adults were given three injections of hepatitis B vaccine (days 0, 30, and 180), and serum samples were obtained on days 0, 21, 51, and 201. A fourfold or greater increase of IgG antibodies within 201 days was detected in 18 individuals (geometrical mean increase 26-fold), but final IgG antibody concentrations (0.3-3 micrograms/ml) were low. Some vaccines had almost reached peak concentration on day 21, in others a great increase was observed between days 21 and 51, and in a few individuals between days 51 and 201. IgG1 was the predominant subclass in the antibodies of most individuals. Ninety-five per cent of all IgG antibodies were IgG1 in early samples of early responders. In late samples of all vaccinees the average proportion of IgG1 antibodies was 78%. The proportion of IgG2 antibodies was slightly higher in late samples (average 12%) than in the early samples of the early responders, (average less than 6%, P less than 0.05). Considerable amounts of IgG3 and IgG4 antibodies were found in one vaccine, but on the average the proportion of IgG3 or IgG4 antibodies was low (less than 6%).

Isotype concentrations of human antibodies to group A meningococcal polysaccharide

Antibodies to meningococcal group A polysaccharide (MenA) in the sera of 34 vaccinated adults were quantitated by an isotype-resolving solid-phase RIA (IgA, IgM, IgG1, IgG2, IgG3, and IgG4). All individuals had antibodies before vaccination. The geometric mean concentration was 2.9 micrograms/ml. Two weeks after vaccination the mean antibody concentration had trebled. Average proportions of the three isotypes were then as follows: IgA 15%, IgM 48%, IgG 37%. No differences were found between individuals who had been immunized with the polysaccharide 7 to 8 yr earlier and "primary responders." The subclass composition of IgG antibodies was determined in the 24 postvaccination samples with a definite IgG response (greater than 2-fold increase). IgG1 was the predominant subclass in antibodies of some sera and IgG2 in others, but the average proportions of both subclasses were nearly the same. IgG3 and IgG4 were only found in occasional sera, but when present, each subclass accounted for up to 6%. Although the ratio of kappa and lambda chains could not be determined, there was evidence to suggest that it was higher in anti-MenA antibodies than in antibodies to protein antigens.

Isotype concentrations of human antibodies to group A meningococcal polysaccharide

Antibodies to meningococcal group A polysaccharide (MenA) in the sera of 34 vaccinated adults were quantitated by an isotype-resolving solid-phase RIA (IgA, IgM, IgG1, IgG2, IgG3, and IgG4). All individuals had antibodies before vaccination. The geometric mean concentration was 2.9 micrograms/ml. Two weeks after vaccination the mean antibody concentration had trebled. Average proportions of the three isotypes were then as follows: IgA 15%, IgM 48%, IgG 37%. No differences were found between individuals who had been immunized with the polysaccharide 7 to 8 yr earlier and "primary responders." The subclass composition of IgG antibodies was determined in the 24 postvaccination samples with a definite IgG response (greater than 2-fold increase). IgG1 was the predominant subclass in antibodies of some sera and IgG2 in others, but the average proportions of both subclasses were nearly the same. IgG3 and IgG4 were only found in occasional sera, but when present, each subclass accounted for up to 6%. Although the ratio of kappa and lambda chains could not be determined, there was evidence to suggest that it was higher in anti-MenA antibodies than in antibodies to protein antigens.