Monoclonal antibodies specific for non-glycosylated porcine prolactin and for pituitary porcine prolactin

Glycosylated and non-glycosylated forms of porcine pituitary prolactin were prepared using Concanavalin A Sepharose chromatography. Anti-prolactin monoclonal antibodies were screened for their ability to distinguish these two forms. One monoclonal antibody (17D9) exhibited high affinity binding for the non-glycosylated form of porcine prolactin, but little or no affinity for the glycosylated form. Using this antibody in conjunction with other monoclonals which equally recognize both forms, we developed immunoassays which can be used to determine the amount of the glycosylated vs. non-glycosylated prolactin in serum or other tissue samples.

A double-blind and cross-over comparison of once daily doxazosin and placebo with steady-state pharmacokinetics in elderly hypertensive patients

The alpha 1-adrenoceptor antagonist doxazosin has been compared with placebo in 40 elderly hypertensive patients (mean age 71.4 years). At the end of 10 weeks once daily treatment with doxazosin the mean 24-h post-dose changes in standing and supine blood pressure compared with placebo were -6.9/-5.6 mmHg (systolic/diastolic) and -6.2/-5.5 mmHg respectively. The reductions in standing and supine diastolic blood pressures were statistically significant compared with placebo. At the end of treatment steady-state pharmaco-kinetics were evaluated in 18 patients. The plasma elimination half-life during the dose interval in these patients was 16.1 h (range 10.1-27.1 h) and the median time to peak plasma concentration was 3 h (range 1-4 h). One patient was withdrawn because of adverse effects (headache, weakness, and sweating) during doxazosin treatment. Once daily doxazosin reduced diastolic blood pressure and was well tolerated in these elderly hypertensive patients.

Specific immunoradiometric assay of insulin-like growth factor I with use of monoclonal antibodies

We identified two monoclonal antibodies that bind spatially distinct epitopes on insulin-like growth factor I (IGF-I). Using these two antibodies, we developed a simultaneous, two-site immunoradiometric assay (IRMA) specific for IGF-I. This IRMA has no detectable cross reactivity with insulin, proinsulin, prolactin, or somatotropin, and less than 2% crossreactivity with IGF-II. The assay response varies linearly with IGF-I concentrations of 0-800 micrograms/L in serum; the detection limit is about 10 micrograms/L. A comparison of 26 IGF-I serum values from the IRMA and from a previously reported IGF-I specific RIA gave a correlation coefficient of 0.96 with no substantial bias (slope = 1.10). IGF-I values for serum, as an aid in assessing growth abnormalities, are easily (only three pipetting steps) obtained in less than 4 h.

Specific immunoradiometric assay of insulin-like growth factor I with use of monoclonal antibodies

We identified two monoclonal antibodies that bind spatially distinct epitopes on insulin-like growth factor I (IGF-I). Using these two antibodies, we developed a simultaneous, two-site immunoradiometric assay (IRMA) specific for IGF-I. This IRMA has no detectable cross reactivity with insulin, proinsulin, prolactin, or somatotropin, and less than 2% crossreactivity with IGF-II. The assay response varies linearly with IGF-I concentrations of 0-800 micrograms/L in serum; the detection limit is about 10 micrograms/L. A comparison of 26 IGF-I serum values from the IRMA and from a previously reported IGF-I specific RIA gave a correlation coefficient of 0.96 with no substantial bias (slope = 1.10). IGF-I values for serum, as an aid in assessing growth abnormalities, are easily (only three pipetting steps) obtained in less than 4 h.

Human antibodies to phosphocholine. IgG anti-PC antibodies express restricted numbers of V and C regions

We examined the IgG subclass composition and isoelectric focusing (IEF) spectrotype pattern of naturally occurring human IgG antibodies that bind phosphocholine (PC) and found direct evidence for restricted expression of both V and C regions among these antibodies. In most individuals, the isotype of these IgG anti-PC antibodies was primarily IgG2. However, serum from some individuals contained significant amounts of IgG1 and IgG3 anti-PC antibodies. We also found that in individual sera, anti-PC antibodies are pauciclonal, as demonstrated by restricted spectrotypic patterns of the anti-PC antibodies. The IEF pattern of these antibodies were for the most part unique for each individual. In some sera, certain anti-PC antibodies with isoelectric points of basic pH bound PC conjugated to bovine serum albumin (PC-BSA) but did not bind pneumococcal C-carbohydrate bearing PC determinants. In two individuals, we found that the spectrotypes that bound only PC-BSA were of the IgG1 subclass. Taken together, these findings demonstrate that within individual sera, human antibodies to PC are quite restricted in both V and C region expression, and furthermore, these V and C regions of human Ig may not randomly associate.

Human antibodies to phosphocholine. IgG anti-PC antibodies express restricted numbers of V and C regions

We examined the IgG subclass composition and isoelectric focusing (IEF) spectrotype pattern of naturally occurring human IgG antibodies that bind phosphocholine (PC) and found direct evidence for restricted expression of both V and C regions among these antibodies. In most individuals, the isotype of these IgG anti-PC antibodies was primarily IgG2. However, serum from some individuals contained significant amounts of IgG1 and IgG3 anti-PC antibodies. We also found that in individual sera, anti-PC antibodies are pauciclonal, as demonstrated by restricted spectrotypic patterns of the anti-PC antibodies. The IEF pattern of these antibodies were for the most part unique for each individual. In some sera, certain anti-PC antibodies with isoelectric points of basic pH bound PC conjugated to bovine serum albumin (PC-BSA) but did not bind pneumococcal C-carbohydrate bearing PC determinants. In two individuals, we found that the spectrotypes that bound only PC-BSA were of the IgG1 subclass. Taken together, these findings demonstrate that within individual sera, human antibodies to PC are quite restricted in both V and C region expression, and furthermore, these V and C regions of human Ig may not randomly associate.

Expression of human IgG subclasses

Human immunoglobulin G (IgG) can be divided into four subclasses that are selectively expressed. For instance, carbohydrate antigens preferentially elicit IgG2 antibodies, whereas protein antigens usually elicit IgG1 and IgG3. Elucidating the biological basis of the selective expression of these IgG subclasses is important to our understanding immunodeficiencies and B lymphocyte development. To investigate clinical importance of IgG subclass deficiencies, a sensitive and specific assay has been developed for IgG subclasses using particle concentration fluorescence immunoassay. Preliminary clinical studies have already shown that infection-prone individuals often have selective IgG2 subclass deficiency. Normal levels of IgG2, however, do not rule out an immunodeficiency in the infection-prone individuals because some individuals have normal levels of IgG subclasses and are poorly responsive to antigens of bacteria. Based on animal studies, two contrasting models of B cell development have been advanced. One model of B cell development proposes a single lineage and proposes that a B cell can successively switch and produce any IgG subclass. The other model proposes multiple lineages and proposes that a B cell can express only some IgG subclasses. It has been found by us that anti-PC antibodies are mostly IgG2 with some IgG1, and that the V region of IgG1 anti-PC antibody is different from that of IgG2 antibody. Our finding, therefore, suggests that B cells producing anti-PC antibodies are progeny of not one ancestral B cell that has successively switched, but two independent ancestral B cells. Cellular studies using polyclonal activators also suggest that regulatory mechanisms for IgG1 and IgG3 are different from those of IgG2 and IgG4. Taken together, we favor the multi-lineage model better than the single lineage model of human B cell development.

The assessment in man of the beta-adrenoceptor blocking activity and cardioselectivity of H-I 42 BS, a long acting beta-adrenoceptor blocking drug

The pharmacokinetic and pharmacodynamic effects of the beta-adrenoceptor antagonist H-I 42 BS were examined in healthy subjects. In an open dose ranging study, H-I 42 BS 50, 100, 200 and 400 mg were given as single oral doses to four subjects. H-I 42 BS 400 mg caused maximum reduction in exercise heart rate (20.4 +/- 1.0%--mean +/- s.d.) at 4 h and still reduced exercise heart rate at 96 h (18.4 +/- 7.2%). Seven subjects received in double-blind, randomised order, single oral doses of H-I 42 BS 50, 100 and 200 mg, atenolol 50 and 100 mg and placebo. H-I 42 BS 400 mg was given in a single blind manner as the last dose of the study. Both H-I 42 BS and atenolol reduced supine and standing heart rate and systolic blood pressure (P less than 0.05) although atenolol had the more marked effect. The maximum percent reduction of exercise heart rate after H-I 42 BS 50 mg was 10.9 +/- 7.1%, after 100 mg was 18.7 +/- 5.8%, after 200 mg was 20.6 +/- 6.4% and after 400 mg was 21.9 +/- 8.2%. H-I 42 BS 400 mg still caused 11.0 +/- 3.5% reduction at 168 h. Atenolol 50 mg caused maximum percent reduction of exercise heart rate of 26.0 +/- 6.0% but did not reduce exercise heart rate after 24 h. The mean peak plasma concentrations for all doses of H-I 42 BS occurred at 5.1 +/- 1.5 h. The plasma elimination half-life was 47.6 +/- 8.1 h. There was a linear correlation between the dose and AUC0-infinity (r = 0.97). The cardioselectivity of H-I 42 BS and atenolol was compared. Six subjects received in double-blind random order H-I 42 BS 100 and 400 mg, atenolol 50 mg and placebo. After each dose, graded infusions of isoprenaline were given until the heart rate increased by 50 beats min-1. Dose-response curves for heart rate, diastolic blood pressure, forearm blood flow and finger tremor were constructed. There was no difference in the dose-response curves for forearm blood flow or finger tremor after H-I 42 BS 400 mg or atenolol 50 mg. Atenolol 50 mg caused more attenuation (P less than 0.01) of the diastolic blood pressure response. These results indicate that H-I 42 BS is a cardioselective beta-adrenoceptor antagonist with a long duration of action in man.

Subclass distribution of human antibodies to Haemophilus influenzae type b capsular polysaccharide

The polysaccharide (PS) capsule of Haemophilus influenzae type b (Hib) is a "simple" antigen, polyribosylribitolphosphate. Although similar carbohydrate antigens have been reported to elicit IgG antibodies relatively restricted to the IgG2 subclass in man, we report here that Hib PS elicits substantial quantities of both IgG1 and IgG2 serum antibodies in most individuals. Because the determination of IgG subclass distribution can be technically difficult, we used four different approaches to establish our finding. First, we used an IgG subclass-specific, antigen-specific "sandwich assay." Second, we measured IgG subclasses of purified antibodies to Hib PS. Third, we showed that significant amounts of IgG anti-PS can be absorbed with a monoclonal anti-IgG1 affinity column. Fourth, we showed that IgG1 and IgG2 fractions of immune sera have clonally restricted anti-Hib PS antibodies that are easily distinguishable by their isoelectric points. The data indicate that both IgG1 and IgG2 contribute substantially to the IgG antibody response of most adults to immunization with Hib PS.

Subclass distribution of human antibodies to Haemophilus influenzae type b capsular polysaccharide

The polysaccharide (PS) capsule of Haemophilus influenzae type b (Hib) is a "simple" antigen, polyribosylribitolphosphate. Although similar carbohydrate antigens have been reported to elicit IgG antibodies relatively restricted to the IgG2 subclass in man, we report here that Hib PS elicits substantial quantities of both IgG1 and IgG2 serum antibodies in most individuals. Because the determination of IgG subclass distribution can be technically difficult, we used four different approaches to establish our finding. First, we used an IgG subclass-specific, antigen-specific "sandwich assay." Second, we measured IgG subclasses of purified antibodies to Hib PS. Third, we showed that significant amounts of IgG anti-PS can be absorbed with a monoclonal anti-IgG1 affinity column. Fourth, we showed that IgG1 and IgG2 fractions of immune sera have clonally restricted anti-Hib PS antibodies that are easily distinguishable by their isoelectric points. The data indicate that both IgG1 and IgG2 contribute substantially to the IgG antibody response of most adults to immunization with Hib PS.

Spontaneous secretion of IgG subclasses by intestinal mononuclear cells: differences between ulcerative colitis, Crohn's disease, and controls

Spontaneous IgG and IgG subclass secretion patterns by isolated intestinal mononuclear cells (MNC) from control and inflammatory bowel disease (IBD) specimens were examined. Intestinal MNC from IBD specimens spontaneously secreted more total IgG than did control intestinal MNC. This increased spontaneous IgG secretion by ulcerative colitis intestinal MNC was primarily due to markedly increased production of IgG1. Slightly increased secretion of IgG3, but not IgG2 by ulcerative colitis intestinal MNC was present when compared with control and Crohn's disease intestinal MNC. In contrast, Crohn's disease intestinal MNC exhibited increased spontaneous secretion of all the IgG subclasses examined, with IgG2 being predominant.

Patterns of contraceptive pill taking in an inner city practice

A total of 161 patients completed a questionnaire about their pattern of taking the oral contraceptive pill. Only 28% (45) of patients were taking the pill according to the manufacturer's instructions, and in the event of the pill being missed only 26% of patients would use a sheath. A tenth of the patients believed that amenorrhoea always indicated pregnancy, but 35% believed that amenorrhoea was harmful to the body. This group did not differ in their pill taking from the remaining 65% of patients.

Turbidimetric assay of IgG with use of single monoclonal antibodies

We describe a turbidimetric assay for quantifying total immunoglobulin G (IgG) in serum with use of a single monoclonal antibody. The reaction, monitored by a centrifugal analyzer, is technically simple, rapid, and precise. Buffer of low ionic strength and polyethylene glycol are required for formation of detectable antibody-antigen complexes. We measured IgG concentrations in 49 polyclonal sera (Group 1) and 84 sera containing monoclonal IgG (Group 2) in assays in which we used either of two anti-IgG monoclonal antibodies (HG6 or HG8). Results compared well with those obtained with a nephelometric assay involving polyclonal antiserum, except for sera from four persons of Group 2 whose immunoglobulins were not detected by antibody HG6. HG6 bound IgG from these four sera in a solid-phase binding assay. HG6 and HG8 recognize epitopes on the Fab and Fc regions of IgG, respectively, and they do not compete for binding to the whole molecule. However, use of the two monoclonal antibodies combined failed to improve the sensitivity or range of the assay. We conclude that light-scattering assays of IgG can be validly performed with a single monoclonal antibody.

Turbidimetric assay of IgG with use of single monoclonal antibodies

We describe a turbidimetric assay for quantifying total immunoglobulin G (IgG) in serum with use of a single monoclonal antibody. The reaction, monitored by a centrifugal analyzer, is technically simple, rapid, and precise. Buffer of low ionic strength and polyethylene glycol are required for formation of detectable antibody-antigen complexes. We measured IgG concentrations in 49 polyclonal sera (Group 1) and 84 sera containing monoclonal IgG (Group 2) in assays in which we used either of two anti-IgG monoclonal antibodies (HG6 or HG8). Results compared well with those obtained with a nephelometric assay involving polyclonal antiserum, except for sera from four persons of Group 2 whose immunoglobulins were not detected by antibody HG6. HG6 bound IgG from these four sera in a solid-phase binding assay. HG6 and HG8 recognize epitopes on the Fab and Fc regions of IgG, respectively, and they do not compete for binding to the whole molecule. However, use of the two monoclonal antibodies combined failed to improve the sensitivity or range of the assay. We conclude that light-scattering assays of IgG can be validly performed with a single monoclonal antibody.

Correlation of serum immunoglobulin subclass concentrations with antibody responses of children to immunization with Haemophilus influenzae type b polysaccharide-pertussis vaccine

Children less than 24 months of age respond poorly to immunization with the capsular polysaccharide of Haemophilus influenzae type b. Because human antibodies to polysaccharide antigens are relatively restricted to IgG2, a late-maturing subclass, we examined the relationship between serum subclass concentrations and anticapsular antibody responses of 41 healthy children, 9 to 38 months of age, following immunization with type b polysaccharide mixed with pertussis vaccine. Both total and IgG anticapsular antibody responses correlated significantly with preimmune serum concentrations of IgG2 but not with those if IgG1. This correlation was age dependent, however, and after the effect of age was removed by partial correlation, the correlation between anticapsular antibody responses and serum IgG2 concentrations was no longer significant. These findings indicate that the ability to respond to this vaccine coincides with maturation of the ability to secrete immunoglobulin of the IgG2 subclass; however, individual variation in IgG2 that is independent of age does not correlate with antibody response to the type b polysaccharide.

Inaccurate values for direct bilirubin with some commonly used direct bilirubin procedures

We compared five methods for the determination of total and direct bilirubins in serum samples from normal controls, subjects with Gilbert's syndrome, and serum pools containing about 50 and 150 mg of total bilirubin per liter. The Kodak Ektachem method and a diazotized sulfanilic acid method with 0.15 mmol/L sodium nitrite concentrations are the only methods that gave accurate direct bilirubin values, as judged by liquid-chromatographic results. The aca method that involved p-nitrobenzene diazonium tetrafluoroborate and another diazotized sulfanilic acid method with a higher concentration of sodium nitrite (0.8 mmol/L) yielded falsely high values for direct bilirubin, which could lead to clinical confusion. The more recently introduced diazotized sulfanilic acid method of the aca gave substantially better results than the p-nitrobenzene diazonium tetrafluoroborate method but was still inaccurate. Systematic investigation of these procedures revealed that the overestimation of direct bilirubin by the diazotized sulfanilic acid method was related to the amount of unconjugated bilirubin present and its ability to react as direct bilirubin in the presence of higher concentrations of sodium nitrite. Inherent properties of p-nitrobenzene diazonium tetrafluoroborate appeared to be responsible for inaccuracies in that method, which could not be corrected by varying reagent concentration or the reaction conditions.

Inaccurate values for direct bilirubin with some commonly used direct bilirubin procedures

We compared five methods for the determination of total and direct bilirubins in serum samples from normal controls, subjects with Gilbert's syndrome, and serum pools containing about 50 and 150 mg of total bilirubin per liter. The Kodak Ektachem method and a diazotized sulfanilic acid method with 0.15 mmol/L sodium nitrite concentrations are the only methods that gave accurate direct bilirubin values, as judged by liquid-chromatographic results. The aca method that involved p-nitrobenzene diazonium tetrafluoroborate and another diazotized sulfanilic acid method with a higher concentration of sodium nitrite (0.8 mmol/L) yielded falsely high values for direct bilirubin, which could lead to clinical confusion. The more recently introduced diazotized sulfanilic acid method of the aca gave substantially better results than the p-nitrobenzene diazonium tetrafluoroborate method but was still inaccurate. Systematic investigation of these procedures revealed that the overestimation of direct bilirubin by the diazotized sulfanilic acid method was related to the amount of unconjugated bilirubin present and its ability to react as direct bilirubin in the presence of higher concentrations of sodium nitrite. Inherent properties of p-nitrobenzene diazonium tetrafluoroborate appeared to be responsible for inaccuracies in that method, which could not be corrected by varying reagent concentration or the reaction conditions.

Relation of age, race, and allotype to immunoglobulin subclass concentrations

Concentrations of IgG1, IgG2, and total IgG were measured by a solid phase radioimmunoassay in sera from 36 healthy adults and 114 healthy children. As expected, IgG2 and total IgG had a positive correlation with age in children. In addition to age, several other factors were associated with significant differences in serum subclass concentrations. Female children had higher concentrations of IgG1 than males, and black subjects had significantly higher concentrations of IgG1, IgG2, and total IgG than whites. Although Km(1) and Gm(23) immunoglobulin allotypes had no relation to subclass concentrations when tested as single factors, the Km(1) allotype interacted significantly with race so that Km(1)-positive black children had higher IgG2 concentrations than other subjects. Our findings may explain, in part, recent observations of an association of the Km(1) allotype with altered immune responses of blacks to certain vaccines containing bacterial polysaccharides. In addition, our data indicate the need to control factors such as sex, race, and allotype in studies of subclass concentrations or immune responses.

Mitogen-induced human IgG subclass expression

To investigate human isotype expression among lymphocyte populations, we have studied IgG subclass production by splenocytes, tonsil cells, and peripheral blood lymphocytes (PBL) after stimulation with a panel of nine mitogens. Response magnitudes varied with tissues: all mitogens produced the strongest responses with splenocytes and the smallest with PBL. In addition, the IgG subclass maximally stimulated by a particular mitogen also depended on the tissue studied. For example, LPS mainly stimulated IgG2 in PBL and IgG1 in spleen. Interestingly, the response patterns seen in splenocytes suggest a large and coordinate expression of IgG1 and IgG3 subclasses. Implications of these findings are discussed with respect to immunoglobulin gene organization and human disease states.

Mitogen-induced human IgG subclass expression

To investigate human isotype expression among lymphocyte populations, we have studied IgG subclass production by splenocytes, tonsil cells, and peripheral blood lymphocytes (PBL) after stimulation with a panel of nine mitogens. Response magnitudes varied with tissues: all mitogens produced the strongest responses with splenocytes and the smallest with PBL. In addition, the IgG subclass maximally stimulated by a particular mitogen also depended on the tissue studied. For example, LPS mainly stimulated IgG2 in PBL and IgG1 in spleen. Interestingly, the response patterns seen in splenocytes suggest a large and coordinate expression of IgG1 and IgG3 subclasses. Implications of these findings are discussed with respect to immunoglobulin gene organization and human disease states.

Effects of azotemia on results of the boronate-agarose affinity and ion-exchange methods for glycated hemoglobin

We evaluated the effect of azotemia on results for glycated hemoglobin as measured by a boronate-agarose affinity method and an ion-exchange chromatographic procedure with saline preincubation and found a good correlation. However, values for glycated hemoglobin in samples from nondiabetic patients with various degrees of azotemia were consistently higher with the ion-exchange column procedure (mean, 8.5%) than with the boronate affinity method (mean, 6.2%). The latter method may thus be preferred for monitoring glycated hemoglobin in diabetic patients with impaired renal function.