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Biomedical subjects

A Ranki

Publications and source records attributed to A Ranki.

At least 73 records · Page 4Linked to original sources
PubMed1993

Evidence against keratin gene mutations in a family with ichthyosis hystrix Curth-Macklin.

Ichthyosis hystrix Curth-Macklin is a rare autosomal dominant disease characterized clinically by hyperkeratosis and ultrastructurally by disruption of the keratin intermediate filament network of suprabasal keratinocytes. We have used linkage analysis to test whether a keratin gene mutation might underlie this disease. This analysis excluded the keratin gene loci as the sites for the disease-causing mutation in one affected kindred.

Chromosomes, Human, Pair 12↗
PubMed1993

An improved enrichment method for functionally competent, highly purified peripheral blood dendritic cells and its application to HIV-infected blood samples.

Dendritic cells (DC) were purified from human peripheral blood using a rapid and simple method based on magnetic depletion of phagocytes with carbonyl iron, followed by centrifugation of nonphagocytic cells on a Percoll density gradient and depletion of lymphocytes and macrophages/monocytes with a panel of MoAbs and immunomagnetic beads. Enriched DC were obtained with > 99% purity as judged by non-specific esterase (NSE) staining. After isolation, these cells, representing 0.4% of the starting mononuclear cell population, still function as potent antigen-presenting cells for purified T lymphocytes. The present results confirm the ability of human peripheral blood DC to present soluble antigens to T cells including microbial antigens and show, further, that DC are more potent soluble antigen-presenting cells than monocytes. The method was successfully applied to the purification of DC from the blood of HIV-infected individuals. We could not detect decreased numbers of DC in four individuals with early HIV infection and no replicating HIV was detected by in situ hybridization in the DC.

Antigen-Presenting Cells↗
PubMed1993

Helper T-cell recognition of HIV-1 Tat synthetic peptides.

The regulatory proteins coded by the human immunodeficiency virus, (HIV)-1 genome are expressed by the infected cells before the initiation of the synthesis of structural proteins and thus immune response directed against these proteins could destroy infected cells before the release of infectious virions. The evaluation of T-lymphocyte responses toward Tat, one of the main HIV-1 regulatory proteins, is therefore of interest. We selected a group of HIV-infected patients with retained response to the recall antigen purified protein derivative and tested their CD4+ helper T-cell response toward recombinant Tat and toward 12 soluble synthetic partially overlapping 15-16-mer Tat peptides in a proliferation assay. Three peptides (amino acids 17-32, 33-48, and 65-80) were significantly recognized by the helper T-cells from infected individuals but not by the nine HIV-1-negative control persons. Nine of the 14 patients (64%) responded to at least one of these Tat peptides. Of the identified immunodominant peptides containing T-cell epitopes, one (aa 65-80) was recognized in association with human leukocyte antigens DR-2 allele, while the others appeared to be promiscuous and were equally recognized in association with several DR molecules. The identified immunogenic peptides were analyzed for the predicted presence of T-cell antigenic sites by several algorithms and positive correlation was detected for each peptide. Our results thus indicate that Tat protein can induce a cell-mediated immune response and identify three peptides containing T-cell epitopes that may be of importance in vaccine development.

Alleles↗
PubMed1992

Antibodies to retroviral proteins in autoimmune connective tissue disease. Relation to clinical manifestations and ribonucleoprotein autoantibodies.

OBJECTIVE: To study the relationship between antibodies that recognize human retroviral proteins and the presence of clinical features and ribonucleoprotein antibodies in patients with autoimmune connective tissue diseases (CTDs). METHODS: Antibodies against native human immunodeficiency virus type 1 (HIV-1) and human T cell leukemia/lymphoma virus type I, recombinant HIV-1 Nef protein, and ribonucleoprotein antigens were determined by immunoblot of sera from 65 prospectively studied patients with definite or suspected CTDs of autoimmune type. RESULTS: Antibodies to retroviral proteins (ARP), most frequently to HIV Gag proteins p55 and p24, were found in 64% of 22 patients with systemic lupus erythematosus (SLE), in 63% of 8 patients with discoid LE (DLE), in 75% of 8 patients with mixed connective tissue disease (MCTD), and in 26% of 19 individuals with chronic biologically false-positive (CBFP) seroreactions, but not in 8 patients with subacute cutaneous lupus erythematosus. No clear correlation of ARP with antibodies to any specific small nuclear RNP antigen was observed. The most striking finding was that recurrent infections, both in LE patients and in those with CBFP reactions and widespread, acral discoid skin lesions, occurred significantly more often in ARP-positive patients. CONCLUSION: The occurrence of antibodies reacting with human retroviral proteins is associated with severe skin lesions and recurrent infections in SLE, DLE, and MCTD patients, and with a disposition toward developing systemic disease in CBFP reactors.

Adolescent↗
PubMed1992

Fine specificity of the B-cell epitopes recognized in HIV-1 NEF by human sera.

We have previously used partially overlapping synthetic nonapeptides to characterize the human natural antibody response against HIV-1 negative regulatory factor (NEF), and identified nine 5 to 13 amino acid long regions that were recognized by sera of HIV-1-infected individuals. In this report we define the minimal size of these epitopes with the use of shorter, from 3 to 8 amino acid long partially overlapping peptides covering the complete sequence of the previously identified reacting regions and the N- and C-terminal flanking sequences. We also introduce a new method for the analysis of the reactivities obtained with peptides of different lengths. In six of the antigenic regions the epitopes were found to be noncontiguous and to consist of multiple, down to three amino acid long separate reactive stretches (epitope 1: WSK, VGW, TVRERMRR; epitope 3A: PLRPM, SHFLK; epitope 3B: SQRRQD, DLW; epitope 3C: IYHT, QGYFPDWQN; epitope 4: SLL, VSL; epitope 5: EVLEWRFDSR, VAR). Three epitopes were clearly linear (epitope 2: CAWLE; epitope 3D: LTFGWC; epitope 6: PEYF). Interestingly, five of the minimized B-cell epitopes (1, 3A, 3C, 3D, 5) recognized by human sera overlap totally or partly with the previously identified T-cell epitopes in HIV-1 NEF. Also, only three of the epitopes (3C, 3D, 5) were in a computer-based homology search shown to contain strictly NEF-specific sequences.

Amino Acid Sequence↗
PubMed1992

Immunological variation and immunohistochemical localization of HIV-1 Nef demonstrated with monoclonal antibodies.

OBJECTIVE: To study the immunological and immunohistochemical nature of HIV-1 Nef. DESIGN: Monoclonal anti-Nef antibodies were generated and used to identify antigenic epitopes in Nef, to study immunological cross-reactivity between Nef from different isolates and to reveal the subcellular localization of Nef. METHODS: Monoclonal antibodies against recombinant HIV-1 Nef protein (BRU isolate) were generated in BALB/c mice. The epitope mapping was carried out with the use of overlapping 15-20mer lipopeptides linked to a lipid group at the amino-terminus. Immunoperoxidase method was used for histochemical studies. RESULTS: Ten stable antibody-producing clones, mainly of the immunoglobulin (Ig) G1 subtype, with strong Western blot and enzyme-linked immunosorbent assay reactivity toward the recombinant Nef protein, were obtained. The epitopes recognized were located on amino-acid sequences 21-41, 31-50, 51-71, 61-80, 151-170, 161-180, and 171-190. All 10 monoclonal antibodies also reacted with the native Nef of HIV-1BRU, and eight reacted with native HIV-1IIIB. Most antibodies also reacted with Nef from more divergent HIV-1 strains. In Western blotting, two forms of Nef (24 and 27 kDa) were observed with most isolates studied. Immunohistochemical staining of HIV-1-infected H9 or MT-4 lymphoid cells demonstrated that Nef was expressed mainly in the Golgi complex and at the nuclear membrane, but occasionally also in the nucleus. The nuclear localization of Nef was especially frequent in the HIV-1-infected MT-4 cells. CONCLUSIONS: Our findings suggest that Nef is expressed in two isomorphic forms, and that it may also act as a nuclear protein and thus have a direct regulatory function at the RNA/DNA level.

Animals↗
PubMed1992

Serological responses to mycoplasmas in HIV-infected and non-infected individuals.

OBJECTIVE: To assess the frequency of mycoplasma infections in HIV-antibody-positive and -negative individuals by studying the serological responses against mycoplasmas, especially Mycoplasma fermentans and M. pirum. DESIGN: An enzyme-linked immunosorbent assay (ELISA) was used to measure immunoglobulin G (IgG) class antibody concentrations against six mycoplasma species in sera of HIV-positive and HIV-negative individuals. METHODS: Serum samples were obtained from 30 HIV-positive individuals (10 asymptomatics, 10 with lymphadenopathy syndrome and 10 with AIDS), 10 HIV-negative partners of HIV-positive individuals and 40 HIV-negative blood donors. Antibodies to M. fermentans strains incognitus and PG18, M. pirum, M. genitalium, M. pneumoniae and M. hominis were assessed by immunoblot or ELISA. Absorbance values were taken as a semiquantitative measurement for antibody concentration and an arbitrary cut-off value (0.8) was set to establish seroprevalence. RESULTS: There was no significant difference in the mean IgG concentrations of any of the six mycoplasmas between HIV-positive and HIV-negative groups. Antibody concentrations were also similar in different clinical phases of HIV infection. Antibody concentrations to different mycoplasma strains were compared with each other to reveal eventual cross-reactions caused by shared antigens; the strongest correlation (r = 0.836) was found between M. fermentans strains incognitus and M. pirum antibody concentrations. The correlation between M. fermentans strains incognitus and PG18 was also significant but weaker (r = 0.522). No shared antigens between M. fermentans strain incognitus and M. pirum were demonstrated by immunoblot. CONCLUSIONS: Antibodies against M. fermentans type strain PG18, strain incognitus and against M. pirum are detected infrequently and their presence does not correlate with HIV infection per se or with the clinical stage of HIV infection.

Antibodies, Bacterial↗
PubMed1992

Cellular localization of Nef expressed in persistently HIV-1-infected low-producer astrocytes.

OBJECTIVES: The characterization and localization of HIV-1 Nef highly expressed in permanently infected astrocytes (TH4-7-5) as a model for latent infection of human brain cells. DESIGN: Immunochemical methods are an appropriate tool to investigate expression and localization of cellular proteins. METHODS: Nef expression was analysed by Western blot and immunoperoxidase staining using a panel of monoclonal and polyclonal antibodies. Cellular localization studies were performed by indirect immunofluorescence and subcellular fractionation of TH4-7-5 cells. Myristoylation of Nef was investigated by immunoprecipitation of [3H]myristic acid-labelled cell extract. TH4-7-5 nef gene was cloned and amplified by polymerase chain reaction and the nef nucleotide sequence analysed. RESULTS: Reactivities of various Nef-specific antibodies with Nef antigen in TH4-7-5 cells were demonstrated by Western blot analysis. Immunofluorescence revealed cytoplasmic perinuclear staining of Nef with most antibodies. However, one monoclonal antibody against amino acids 168-175 of Nef showed intense homogeneous nuclear staining in TH4-7-5 cells. Reactivity of this Nef antibody was blocked with recombinant Nef derived from TH4-7-5 cells. After subcellular fractionation, Nef was detected in nuclear, membrane and cytosolic fractions of TH4-7-5 cells. No myristoylated Nef antigen was detectable, perhaps because of a serine residue at position 2 of the TH4-7-5 nef gene instead of the glycine residue required for myristoylation. CONCLUSIONS: Chronically HIV-1-infected astrocytoma cells with restricted virus production express different antigenic forms of Nef, which can be distinguished by their subcellular localization. Variant subcellular targeting of Nef suggests the existence of multiple activities of Nef within HIV-infected cells.

Amino Acid Sequence↗
PubMed1991

Effect of PUVA on immunologic and virologic findings in HIV-infected patients.

Psoralen and UVA radiation inactivate human immunodeficiency virus (HIV) in vitro whereas UVB and UVC radiation under experimental conditions transactivate HIV. We studied the effect of systemic PUVA treatment on immunologic and virologic findings in five HIV-infected patients. Systemic PUVA was given in two-4-week periods, 2 months apart. The total irradiation ranged from 30 to 262 joules/cm2. All skin lesions, including therapy-resistant psoriasis vulgaris, seborrheic dermatitis, folliculitis, and chronic urticaria, cleared during the first weeks of PUVA. A slight increase in the CD4 lymphocyte numbers was seen in two patients. Serum beta 2-microglobulin values and urine neopterin values remained steady, and the elevated serum immunoglobulin values became normal in all patients. The PUVA treatment did not induce appearance of HIV antigen in serum and HIV isolation was repeatedly negative in all patients whose cultures were initially negative. Lymphocyte recall responses to purified protein derivative (tuberculin) became positive in three and to HIV-specific antigens in two patients. These responses, however, were transient. All patients except one, who was positive for HIV antigen at entry, have remained well 1 year after PUVA therapy.

Female↗
PubMed1990

Antibodies against retroviral core proteins in relation to disease outcome in patients with mycosis fungoides.

We have studied the relationship of antibodies reacting with human retroviral core proteins to the disease outcome in Finnish mycosis fungoides (MF) patients in a prospective manner. Antibodies recognizing human T-cell leukaemia/lymphoma virus I (HTLV-I) or human immunodeficiency virus type 1 (HIV-1) core proteins were found in 12 of 14 MF patients as shown by the Western blot method. The antibody reactivities showed three patterns: three patients had antibodies cross-reacting with the gag-encoded core proteins of both HTLV-I and HIV-1; seven patients showed antibodies reacting with HTLV-I core proteins only; and the sera of two patients reacted with HIV p24 core protein only. When following the clinical course of these patients, we found that the three patients with antibodies cross-reacting with both viruses had the most fulminant clinical course, and the overall duration of MF was, on average, 4 years less than in the rest of the patients. None of the patients, however, became leukaemic, or showed any other features suggestive of acute T-cell leukaemia/lymphoma (ATL). Two patients, who did not show anti-retroviral antibodies during the follow-up, had a stable disease with plaque-type skin lesions. Histological or immunohistological typing of the skin infiltrates did not correlate with the disease outcome or the above antibody patterns. Our results thus raise the possibility that an unknown retrovirus, immunologically related to the known human retroviruses, may be aetiologically linked to MF.

Cross Reactions↗
PubMed1990

Antigenic epitopes of NEF proteins from different HIV-1 strains as recognized by sera from patients with manifest and latent HIV infection.

Human immunodeficiency virus (HIV) infection that generally causes a strong antibody response toward HIV may sometimes occur in a latent form, characterized by seronegativity in assays based on structural HIV proteins. Latently infected individuals, however, often have an antibody response against the nonstructural regulatory HIV-1 protein NEF, a factor implicated in down-regulation of viral expression. In order to define the specificity of NEF antibodies, we looked for antibody response against more than 600 overlapping nonapeptides representing the total NEF sequence of three different HIV-1 isolates BRU, SF2, and MAL. Nine distinct homologous antigenic epitopes were recognized by sera from seropositive HIV-1-infected individuals by the peptide ELISA. We further demonstrated that sera from "at risk" individuals, with no antibodies to HIV structural proteins but reacting with the recombinant NEF protein in Western blot, recognize the same epitopes. Immunological assays based on the defined NEF epitopes can therefore be used to diagnose early or latent HIV Infection.

Amino Acid Sequence↗
PubMed1990

Affinity-based collection of amplified viral DNA: application to the detection of human immunodeficiency virus type 1, human cytomegalovirus and human papillomavirus type 16.

We have devised a sensitive and convenient hybridization technique by combining the polymerase chain reaction (PCR) with affinity-based hybrid collection. In this method 5'-biotinylated primers are used to introduce biotin residues into the DNA fragments during the amplification. The amplified DNA fragments are detected by liquid hybridization using a 32P- or 35S-labelled oligonucleotide as probe. For measurement the hybrids are collected on polystyrene microparticles or onto microtitre wells taking advantage of the biotinavidin interaction. The method is highly sensitive allowing the detection of 30 molecules of DNA. It involves few and simple operations, and is thus suitable for routine diagnostics. The applicability of the method to the detection of HIV-1 DNA from blood, HCMV DNA from urine and HPV-16 DNA from cervical scrapes was evaluated.

Base Sequence↗
PubMed1990

Antibodies to recombinant HIV-1 nef protein detected in HIV-1 infection as well as in nonrisk individuals.

Antibodies to the human immunodeficiency virus (HIV) regulatory gene nef (negative factor) product are claimed to be characteristic of early and latent HIV infection. We looked for anti-nef antibodies in individuals infected with HIV or at risk for HIV, in blood donors, and in patients with diverse dermatological disorders. In HIV-infected patients, antibodies to recombinant nef protein were seen by Western blot assay in 29 of 54 (54%) individuals at any time during a prospective follow-up. Except for a decline in the level prior to ARC and AIDS, the occurrence of antibodies did not significantly correlate with any pattern of disease progression in 22 patients followed for up to 4 years. Among the 141 HIV risk group members, negative in recombinant HIV ELISA tests, anti-nef antibodies were detected in 7 (5%) individuals. However, an anti-nef antibody response was also seen in 5 of 93 (5%) nonrisk dermatological patients and in 4 of 37 (11%) healthy blood donors. Solitary HIV gag protein antibody responses were most frequent (7%) in the group of individuals at risk for HIV but the majority of anti-nef positive sera did not react with HIV gag proteins. The relatively frequent occurrence of indistinguishable anti-nef antibody responses in nonrisk individuals suggests that immunological cross-reaction between nef and some cellular regulatory protein may occur.

Female↗
PubMed1989

No evidence for true HTLV-I or HIV-1 antibodies in Finnish Lapps.

Previous seroepidemiologic studies have suggested that in addition to certain subtropical and tropical parts of the world, human T cell leukemia virus type I (HTLV-I) may be endemic in the arctic regions, too. We studied 111 sera collected from original inhabitants of Finnish Lapland with ELISA and Western blot analysis for antibodies to HTLV-I and human immunodeficiency virus type 1 (HIV-1). No true positive sera for either virus were found in the confirmatory Western blot assays, albeit 6 and 2%, respectively, were positive in the screening ELISA assays. Despite the small sample size this survey does not support the hypothesis that HTLV-I would be endemic in the Arctic.

Arctic Regions↗
PubMed1989

Clinical, immunohistochemical, and electron-microscopic findings in gold dermatitis.

The clinical, immunohistochemical, and electronmicroscopic features of 13 consecutive patients with gold dermatitis were analyzed: 12 developed an eczematous dermatitis and one a lichenoid dermatosis. The patients had received intramuscular sodium aurothiomalate therapy from 1 month to 4 years before the dermatitis broke out. After cessation of gold therapy, the dermatitis persisted for 1-11 months. A relatively sparse perivascular mononuclear cell infiltrate was found in the affected skin in all cases. With immunoperoxidase staining, most of the infiltrating cells were shown to be OKT-4-positive T-helper lymphocytes. A majority of the infiltrating cells were Ia, i.e., HLA class II antigen, positive. Clearly increased numbers of dermal OKT-6-positive Langerhans' cells were also seen. In epidermis, on the contrary, the expression of both OKT-6 and Ia markers on dendritic cells was decreased. However, electron-microscopic examination revealed large numbers of macrophage-like cells and the Langerhans cells were activated, often in apposition to mononuclear cells within the epidermis. No correlation was observed between the immunohistological findings and the amount of gold received, the duration of gold therapy, and the interval between the last gold injection and biopsy, respectively, although peripheral blood eosinophilia was more common during 5-10 months of gold therapy. There were no specific findings in the patients in whom dermatitis lasted several months after discontinuation of the therapy. Our findings support the view that immunological mechanisms operate in the development of gold dermatitis, although the exact mechanisms remain unknown.

Adolescent↗
PubMed1989

T-cell response towards HIV in infected individuals with and without zidovudine therapy, and in HIV-exposed sexual partners.

HIV-specific T-cell response in HIV-infected individuals at different stages of the disease and during zidovudine therapy was studied using HIV and HIV-envelope derived native and recombinant proteins as antigens. Neither antibody-negative at-risk individuals nor HIV-infected individuals responded to HIV or its envelope-derived proteins, even though they responded to a recall antigen, purified protein derivative of tuberculin (PPD). However, five out of 14 antibody- and antigen-negative sexual partners of known HIV-positive men did respond to HIV, native gp 120 and recombinant envelope and core proteins. Some AIDS-related complex (ARC) and AIDS patients treated with zidovudine also showed a low T-cell response which diminished along with clinical deterioration. A synthetic peptide representing one of the major T-cell epitopes in HIV envelope, frequently recognized by immunized and infected primates, gave only marginal stimulation in man. Our findings suggest that HIV infection in man results in a T-helper cell anergy directed against viral proteins. The response observed in the antibody- and antigen-negative sexual partners and in some of the zidovudine-treated patients implies that at least some epitopes on HIV envelope are immunogenic in man.

Acquired Immunodeficiency Syndrome↗