Human anti-mouse antibody response induced by anti-CD4 monoclonal antibody therapy in patients with rheumatoid arthritis

The development of human anti-mouse monoclonal antibodies (HAMAs) was investigated in 10 patients with rheumatoid arthritis (RA) who had undergone an experimental therapeutic trial with an anti-CD4 monoclonal antibody. In this patient group, the antibody 16H5 of the IgG1 isotype had been administered in a median total dosage of 140 mg per treatment cycle. Four patients took part in a second treatment regimen 6-8 weeks later. After the first treatment cycle, detectable HAMAs developed in 5 out of 10 patients. In 4 individuals undergoing a second course of therapy, increases of HAMAs were evident only in the 3 patients with previous HAMA responses. HAMAs were primarily of the IgG isotype, while the presence of rheumatoid factors usually interfered with the detectability of IgM HAMAs. However, using isolated F(ab)2 fragments of the monoclonal reagent used for therapy, HAMAs of the IgM isotype were also detectable. HAMAs of the IgG isotype did not exceed levels of 2.0 mg/liter after a single treatment cycle and 2.2 mg/liter after a repeated cycle. No IgE responses were detectable. Absorption experiments indicated that approximately 25% of the HAMA activity was directed against specific determinants of the 16H5 monoclonal antibody, presumably including anti-idiotypic reactivities. These data demonstrate that HAMAs developed only in a proportion of RA patients treated with the anti-CD4 monoclonal antibody 16H5. However, the amounts were rather low compared to other monoclonal reagents used in cancer patients and were therefore allowed for repeated applications without an apparent loss of efficacy.     

Acidotropic amines inhibit proteolytic processing of flavivirus prM protein

Treatment of flavivirus-infected mammalian and mosquito cells with acidotropic amines (such as chloroquine, ammonium chloride, or methylamine) inhibited the normal proteolytic processing of the virus prM protein to M. As a result, virions from infected cells which had been treated with acidotropic amines late in the virus replication cycle contained prM protein rather than M protein. Identification of the prM protein was based on molecular weight, glycosylation, and reactivity with an anti-prM monoclonal antibody. Infected cells which had not been treated with acidotropic amines did release, along with virions which contained the mature M protein, variable amounts of virus containing the prM precursor. The relative amounts of these two types of virions were influenced both by the virus and the host cell type. Virions containing the prM protein had a lower specific infectivity than virions containing the M protein; however, in experiments with a macrophage cell line this low specific infectivity was significantly increased if the anti-prM monoclonal antibody was used to facilitate virus entry via Fc receptors. Our findings indicate that the proteolytic cleavage of prM requires an acidic environment and is necessary to generate fully infectious virus. We suggest that the cleavage of prM occurs in the acidic post-Golgi vesicles.     

The effect of RANTES chemokine genetic variants on early HIV-1 plasma RNA among African American injection drug users

HIV-1 plasma RNA is a prognostic indicator of HIV-1, and increased levels of HIV-1 plasma RNA are associated with rapid progression to AIDS. Because chemokines and chemokine receptors are involved in the binding and entry of HIV-1, possible effects of host genetics on viral RNA levels should be visible in early infection. HIV-1 plasma RNA was measured within 2 years of seroconversion in 198 seroincident injection drug users followed in the AIDS Link to Intravenous Experience cohort. Genetic variants were identified in the chemokine receptors (CCR2, CCR5, and CCR5 promoter) and the chemokine RANTES using TaqMan and restriction fragment length polymorphism assays. Linear regression of RANTES haplotypes on early HIV-1 plasma RNA identified individuals homozygous for the RANTES R1 haplotype as having a lower viral load by almost one-half log10 unit compared with those bearing non-RANTES R1 haplotypes (-0.43, 95% confidence interval: -0.74, -0.12). Genetic variants in RANTES may downregulate RANTES gene expression and increase early HIV-1 plasma RNA. Because RANTES is a critical chemokine and competitively inhibits HIV-1 by binding to its receptor CCR5, treatment to enhance RANTES expression may assist in delaying the progression of AIDS by decreasing the initial viral load.     

HLA diversity, differentiation, and haplotype evolution in Mesoamerican Natives

Genetic variation of the Human Leukocyte Antigen region (HLA) in three Amerindian populations from the Southern Mexican state of Oaxaca, the Zapotec, Mixtec and the Mixe is examined. Individuals were typed using PCR-SSOP for four class II loci (DRB1, DQA1, DQB1, DPB1) and three class I loci (HLA-A, -B, and -C). Based on known HLA distributions, European admixture ranged from 1% to 10%. Individuals with European alleles were excluded from subsequent analysis. New alleles were revealed at each of the class I loci. In general, genotype frequencies were in Hardy-Weinberg equilibrium, although some deviations were detected. Allele frequency distributions at the DRB1, DQA1, DQB1 and HLA-A loci in all populations were more even than expected under neutrality, supporting a model of balancing selection at these loci. A history of directional selection for DPB1 in all three populations was indicated, as homozygosity values were significantly above expected values. Allele frequency distributions at HLA-B and HLA-C did not differ significantly from neutrality expectations. The data also provide evidence from linkage disequilibrium that strong haplotypic associations are present across the entire HLA region in each of the populations. Significant overall linkage disequilibrium exists between all pairs of loci typed in these populations, except those which include the DPB1 locus. These associations exist despite the fact that the recombination fraction between HLA-A, in the class I region, and DQB1, in the class II region, may exceed 0.02. One explanation is that selective pressures are maintaining the relationships between particular alleles at these loci in these populations. These relationships are maintained in general across the entire HLA region in the Oaxacan Amerindians, with the exception of DPB1.     

Chronopharmacokinetics of beta-receptor blocking drugs of different lipophilicity (propranolol,metoprolol, sotalol,atenolol) in plasma and tissues after single and multiple dosing in the rat

Summary Comparative pharmacokinetic studies with the -receptor blocking drugs propranolol, metoprolol, sotalol and atenolol, differing greatly in lipophilicity, and their main route of elimination were performed in light-dark-synchronized rats after equimolar single (6 moles/kg) or multiple (6x6 moles/kg) drug application. Drug concentrations were determined in plasma and various target organs of the drugs, e.g. heart, muscle, lung and brain, after drug application in the light period (L) and dark period (D), respectively. After single drug administration pharmacokinetic parameters of all drugs depended on the L and D conditions. Elimination half-lives in plasma and organs were shorter during D than during L. No L-D-differences were found in initial drug concentrations of the hydrophilic drugs sotalol and atenolol. In contrast, C₀-values of the lipophilic propranolol in highly perfused organs (muscle, lung, brain) and of metoprolol in muscle tissue were significantly higher in D than in L. No obvious temporal dependency was found in other pharmacokinetic parameters (AUC, plasma clearance,V _d) with the exception inV _d of propranolol. Due to the different physico-chemical properties of the compounds inter-drug-differences in pharmacokinetic parameters including drug accumulation into lung and brain tissue were observed. Multiple drug dosing abolished the circadian-phase-dependency in the elimination half-lives of the drugs due to an increase in D. Only for the highly lipophilic propranolol half-lives in highly perfused organs were still shorter in D than in L. It is concluded that L-D-differences in drug half-lives after single dose application are mainly due to circadian variations in drug elimination with a higher hepatic (propranolol, metoprolol) or renal (sotalol, atenolol) elimination in the activity period of rats during D. Additional studies with propranolol on heart rate of conscious rats revealed that a maximum in -receptor blockade was achieved at 10 moles/kg in L but not in D. Thus, it is assumed that abolition of circadian-phase-dependency in half-lives after 6x6 moles/kg of the drugs may be due to the longer lasting and more pronounced -receptor blockade after multiple drug dosing over a period of several hours in D. Thereby, liver-flow-dependent elimination of propranolol and metoprolol and renal elimination of sotalol and atenolol is reduced to base-line levels found in L.Parts of this work were presented at the 22nd Spring Meeting (Lemmer 1981) and at the Joint Meeting (Lemmer et al. 1983a) of the German Pharmacological Society     

Illness cognitions and health-related quality of life in liver transplant patients related to length of stay,comorbidities and complications

Quality of Life Research - Illness cognitions regarding helplessness and acceptance are known to play a role in health-related quality of life (HRQoL). Our study examined the evolution of these...     

Immunomodulatory Effects of Dietary Polyphenols

Functional and nutraceutical foods provide an alternative way to improve immune function to aid in the management of various diseases. Traditionally, many medicinal products have been derived from natural compounds with healing properties. With the development of research into nutraceuticals, it is becoming apparent that many of the beneficial properties of these compounds are at least partly due to the presence of polyphenols. There is evidence that dietary polyphenols can influence dendritic cells, have an immunomodulatory effect on macrophages, increase proliferation of B cells, T cells and suppress Type 1 T helper (Th1), Th2, Th17 and Th9 cells. Polyphenols reduce inflammation by suppressing the pro-inflammatory cytokines in inflammatory bowel disease by inducing Treg cells in the intestine, inhibition of tumor necrosis factor-alpha (TNF-α) and induction of apoptosis, decreasing DNA damage. Polyphenols have a potential role in prevention/treatment of auto-immune diseases like type 1 diabetes, rheumatoid arthritis and multiple sclerosis by regulating signaling pathways, suppressing inflammation and limiting demyelination. In addition, polyphenols cause immunomodulatory effects against allergic reaction and autoimmune disease by inhibition of autoimmune T cell proliferation and downregulation of pro-inflammatory cytokines (interleukin-6 (IL-6), IL-1, interferon-γ (IFN-γ)). Herein, we summarize the immunomodulatory effects of polyphenols and the underlying mechanisms involved in the stimulation of immune responses.