High rate of HTLV-II infection in seropositive i.v. drug abusers in New Orleans

Confirmed infection with HTLV-II (human T cell leukemia virus type II) has been described only in rare cases. The major limitation to serological diagnosis of HTLV-II has been the difficulty of distinguishing HTLV-II from HTLV-I (human T cell leukemia virus type I) infection, because of substantial cross-reactivity between the viruses. A sensitive modification of the polymerase chain reaction method was used to provide unambiguous molecular evidence that a significant proportion of intravenous drug abusers are infected with HTLV, and the majority of these individuals are infected with HTLV-II rather than HTLV-I. Of 23 individuals confirmed by polymerase chain reaction analysis to be infected with HTLV, 21 were identified to be infected with HTLV-II, and 2 were infected with HTLV-I. Molecular identification of an HTLV-II--infected population provides an opportunity to investigate the pathogenicity of HTLV-II in humans.

Isolation and characterization of carp prolactin

Prolactin (PRL) was extracted with acid-acetone from common carp (Cyprinus carpio) pituitary glands and purified by gel filtration on Sephadex G-75, ion-exchange chromatography on DEAE-cellulose, and reversed-phase high-performance liquid chromatography (HPLC) on TSK-gel TMS 250 with a yield of 0.7 mg/g wet tissue. At each stage of purification, fractions were monitored by HPLC on TSK-gel ODS 120T and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Carp PRL was almost equipotent with ovine PRL in retaining plasma Na concentrations in the hypophysectomized killifish, Fundulus heteroclitus. Immunocytochemistry at both the light and electron microscopic levels revealed that carp PRL antiserum specifically stained cells in the goldfish rostral pars distalis. No cross reaction with putative growth hormone (GH) cells in the proximal pars distalis was observed. The specificity of the carp PRL antiserum was confirmed by immunoblot studies. Although immunostaining of both carp and salmon PRL was observed, there was no cross reaction to GHs from these species. Carp PRL had a sole N-terminal residue of valine, a molecular weight of 23 kDa in SDS-PAGE, and an isoelectric point of 7.3 by gel electrofocusing. Based on these results, together with the knowledge of physicochemical properties of salmon and tilapia PRLs, we propose a standard procedure for isolation of fish PRLs.

Thyrotropic activity of salmon pituitary glycoprotein hormones in the Hawaiian parrotfish thyroid in vitro

The thyrotropic activities of salmon pituitary extract, thyroid-stimulating hormone (TSH), gonadotropins (GTH), and glycoprotein fractions obtained during purification of salmon TSH and GTH were measured using the parrotfish thyroid culture system. Purified salmon TSH was approximately 1,000 times more potent than bovine TSH in stimulating thyroxine release into the culture medium. Most of the forms of salmon GTH had no thyrotropic activity. One of the forms of salmon GTH (GTH-F) and three chromatofocusing fractions (CF-B, -C, and -E) that were devoid of activity in the coho salmon in vivo had some thyrotropic activity in the parrotfish thyroid culture. Whether the activity of these fractions was due to contamination with TSH, less potent forms of TSH, or inherent thyrotropic activity of a form of GTH is discussed. These results indicate that the parrotfish thyroid culture system can be used to detect thyrotropic activity of fractions obtained during the purification of teleost TSH.

Variation in thyroid response to thyroid-stimulating hormone in juvenile coho salmon (Oncorhynchus kisutch)

Changes in the circulating levels of thyroid hormones measured by radioimmunoassay in yearling coho salmon in response to injection of bovine thyroid-stimulating hormone (TSH) were evaluated from January through August. Doses of TSH ranging from 0.2 to 6.4 micrograms/g body wt were ineffective in stimulating T4 in January and at one time in April. Responses to TSH injection at this dose range were observed beginning in February and continuing through August. The minimal effective dose of TSH was either 0.2 or 0.4 microgram/g from May through August. The dose-response relationships of bovine and coho salmon TSH were compared and found to be similar. The time course of response of juvenile salmon to either bovine TSH or partially purified salmon TSH was found to be similar in January, May, and August, although the magnitude of the response differed at these different times. It is concluded that the increase in thyroid response to TSH may play a part in the onset of the increase in circulating T4 at the time of smoltification, but such changes in sensitivity do not explain the decrease in circulating T4 at the completion of smoltification.

Pituitary thyrotropin and gonadotropin of coho salmon (Oncorhynchus kisutch): separation by chromatofocusing

Thyrotropin (TSH) and gonadotropin (GTH) were isolated from adult female coho salmon pituitary glands. After final extraction in acidic alcohol and precipitation in 85% ethanol, proteins were fractionated using gel filtration chromatography and chromatofocusing. Homologous bioassay systems were used to monitor bioactivity during the purification procedures. TSH activity was measured in vivo in coho salmon parr. GTH (steroidogenic) activity was determined in vitro using cultures of adult coho salmon ovarian follicles. Using these procedures, TSH and GTH activities were separated. TSH activity eluted as one major peak at pH 6.3 whereas GTH activity eluted as five major peaks at pH's 5.4, 5.0, 4.7, 4.3, and after 1.0 M NaCl on chromatofocusing. Molecular weights of the TSH and GTHs were estimated by gel filtration chromatography as 35 and 40 kDa, respectively. Like other vertebrate TSHs and gonadotropins, the coho salmon TSH and GTHs appeared to consist of two subunits. Coho salmon TSH and bovine TSH (bTSH) were equipotent in the TSH bioassay. The five coho salmon GTHs exhibited similar potencies in stimulating ovarian estradiol synthesis in vitro. Further biochemical analysis and tests for other gonadotropic activities are warranted to determine if these five GTHs are isoforms of one GTH or if they can be distinguished functionally in other GTH bioassays. Sufficient quantities of coho salmon TSH were isolated in this study for future studies of the hypothalamic-pituitary-thyroid axis in fish.

A 32,000-molecular weight protein from bovine placenta with placental lactogen-like activity in radioreceptor assays

Considerable discrepancies exist in the literature concerning the size and activity of bovine placental lactogen. Our bovine placental lactogen purification preparations were 20% as active as bovine PRL (bPRL) on a per weight basis when compared to bPRL in a lactogenic radioreceptor assay. To identify the active component in these preparations, the proteins were radioiodinated and bound to membrane receptors in the presence and absence of competing hormones, bPRL, and bovine GH (bGH). After centrifugation, membrane pellets were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the gels were autoradiographed. Only one radioiodinated protein band was present. This protein was displaced in the presence of competing hormone and comigrated which a major component of the purification preparations. In radioreceptor assays the active component was as active as bPRL and bGH. From the migration of protein standards included with the radioiodinated purification preparations in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, we estimate that the protein is 32,000 mol wt--about 10,000 mol wt larger than placental lactogens isolated in other species. The possibility that the active molecule was a precursor protein was investigated by examining proteins secreted by bovine placenta tissue cultures. The binding activity in these secretions, as well as in the purification preparations, eluted between ovalbumin (43,000 mol wt) and bPRL (22,000 mol wt) under nondenaturing conditions using high performance gel filtration chromatography. Analysis of this secreted protein, also by binding to membrane receptors, showed that the protein had the same molecular weight as that isolated from the purification preparations and was specifically displaced by the same hormones.

Effects of the uterus and mid-pregnancy conceptus on luteal lifespan of the rat

Hysterectomy on or after Day 10 resulted in a quick return of pseudopregnant rats to oestrus but the interval to oestrus in pregnant rats was significantly longer (P less than 0.01), indicating that the gravid uterine horn interfered with uterine-induced luteolysis by Day 10. When pseudopregnant rats were injected with extracts of conceptuses or pregnant rat serum (PRS), samples collected on Days 10 or 12 of pregnancy delayed the return to oestrus (P less than 0.01 for conceptus extracts, P less than 0.05 for PRS) and serum progesterone concentrations on Day 13 of pseudopregnancy were higher (P less than 0.01) than in controls. Bioassays utilizing mammary development or inhibition of oestrus in virgin cyclic rats as endpoints failed to detect lactogenic activity in Day 10 conceptus extracts or PRS, and radioreceptor assays using bovine prolactin (NIH-B5) as a standard showed that Day 10 extracts had only about 2--3% of the lactogenic activity found in Day 12 extracts. Injections of dilutions of Day 12 extracts with 2 or 4 times the lactogenic activity as Day 10 extracts did not extend pseudopregnancy. These results suggest that by Day 10 the conceptus produces a factor capable of interfering with luteolysis and that this factor is not placental lactogen.

Amplification of the enzyme-linked immunosorbent assay for measuring allergen-specific IgE and IgG antibody

The amplified enzyme-linked immunosorbent assay (a-ELISA) has been successfully applied to the measurement of allergen-specific IgE and IgG antibodies. Data presented indicate a high positive correlation among measurements of IgE-specific antibodies to ragweed antigen E using the a-ELISA, RAST and radiometric assay of Zeiss. Similarly, a high correlation between allergen-specific IgG antibodies measured by the a-ELISA and Farr assay was also observed. Data presented indicate that the measurement of serum IgE antibodies in the linear region of the ELISA titration plot is unaffected by competition with IgG antibodies. The assay is sensitive, reliable, and without risk to laboratory personnel. It is capable of measuring both IgE and IgG antibodies in patients using the same assay system.

An immunochemical approach for the analysis of membrane protein alterations in Ca2+-loaded human erythrocytes

An increase in the intracellular concentration of Ca2+ in human erythrocytes results in the formation of gamma-glutamyl-epsilon-lysine cross-linked membrane protein polymers. Following solubilization of the membranes with SDS, these polymers can be isolated on a Lubrol-containing sucrose gradient. Immunoelectrophoresis of the polymeric material with a polyspecific rabbit antibody against human ghosts gave rise to a single, but heterogeneous, precipitate. The polymer was amphiphilic and, on addition to Triton-solubilized erythrocyte membrane proteins, it coprecipitated with spectrin. When the antihost antibody was absorbed with the polymer prior to cross immunoelectrophoresis of normal erythrocyte membrane proteins, the precipitates of glycophorin, acetylcholinesterase, and hemoglobin were normal, whereas the antibody titers against band 3 protein, spectrin, and ankyrin became reduced. Furthermore, a rabbit antibody raised against the isolated human polymer reacted selectively with the same three membrane proteins. No reactions occurred with lysate proteins.

Amplification of the enzyme-linked immunosorbent assay (ELISA) in the detection of class-specific antibodies

A modification of the standard enzyme-linked immunosorbent assay (ELISA) is described which circumvents the requirement for specifically purified antibodies from which antibody-enzyme complexes are made. The assay utilizes the principle of a soluble anti-alkaline phosphatase immune complex (AP-A-AP) and has been called the amplified ELISA. Methods for preparing and evidence for the specificity of rabbit anti-rat gamma-FC, IgM (mu) and IgA (alpha) are presented. These reagents are used to measure anti-DNP antibodies belonging to classes IgG, IgM and IgA in rat serum. Using antiglobulin and anti-enzyme reagents prepared in guinea pigs, anti-ovalbumin antibodies are measured in rabbit serum. Titration curves are similar when the amplified ELISA is compared to the standard ELISA. A change in slope suggesting an effect of saturation of antigen sites, occurs at the same input antibody concentration for both assays. Determination of the anti-DNP concentration of unknown sera by extrapopulation from titration graphs of a known serum suggests that the value is overestimated, i.e., amplified when the amplified ELISA is used. In addition, the amplified ELISA has an improved ability to detect low levels of antibody. Evidence is presented which illustrates how the use of optimally conjugated DNP-proteins, age of conjugates, and optimal dilutions of secondary antiglobulins and the AP-A-AP reduce non-specific binding in the amplified ELISA. The amplified ELISA is capable of detecting 2.4 ng of antibody to ovalbumin in a one: one million dilution of rabbit serum with high reproducibility and low background.