Synthesis, Biological, and Immunological Properties of Cyclic Peptides from Plasmodium Falciparum Merozoite Surface Protein-1.

Effective structural mimics of a functionally important epitope from the malarial Merozoite Surface Protein-1 (MSP-1) include N-backbone cyclic peptides such as 1. They mimic the interaction of MSP-1 with human erythrocytes and can be used to induce parasite-specific monoclonal antibodies.

Cultivation and characterization of stable Leishmania guyanensis complex axenic amastigotes derived from infected U937 cells.

The study of the differential regulation of several genes, in both Leishmania parasite life cycle forms, has been simplified by the development of in vitro axenic amastigote culture. Different reports have described extracellular amastigote production and maintenance from several Leishmania spp. A general approach to induce amastigote-like transformation includes progressive pH and temperature changes.

GGRGDSPCA peptide: a new antiscarring agent on glaucoma filtration surgery.

Background And Objective: GGRGDSPCA synthetic peptide competes for integrin receptor in scar formation after glaucoma filtering surgery in a rabbit model. The purpose of this study was to evaluate the use of this peptide and compare it with mitomycin on glaucoma filtering surgery.

Materials And Methods: Posterior sclerectomy was performed in both eyes of 17 rabbits.

Mapping of the antigenic determinants of the T. cruzi kinetoplastid membrane protein-11. Identification of a linear epitope specifically recognized by human Chagasic sera.

The high variability among strains and isolates of Trypanosoma cruzi and the existence of shared antigenic determinants with other pathogens, particularly with members of the Leishmania genus make difficult the specific diagnosis of Chagas' disease. The data reported in this paper show that the T. cruzi KMP11 protein is an immunodominant antigen highly recognized by the sera from chagasic and leishmaniasis patients.

Sequence and diversity of DRB genes of Aotus nancymaae, a primate model for human malaria parasites.

The New World primate Aotus nancymaae is susceptible to infection with the human malaria parasite Plasmodium falciparum and Plasmodium vivax and has therefore been recommended by the World Health Organization as a model for evaluation of malaria vaccine candidates. We present here a first step in the molecular characterization of the major histocompatibility complex (MHC) class II DRB genes of Aotus nancymaae (owl monkey or night monkey) by nucleotide sequence analysis of the polymorphic exon 2 segments. In a group of 15 nonrelated animals captivated in the wild, 34 MHC DRB alleles could be identified.

Immunoglobulin kappa light-chain V, J, and C gene sequences of the owl monkey Aotus nancymaae.

Sequences of Aotus nancymaae immunoglobulin kappa light-chain rearrangements were analyzed after reverse transcription polymerase chain reaction. Among 22 in-frame rearrangements analyzed, 12 IGKV genes belonging to the families 1, 2, or 3 were identified. Aotus counterparts for all five human IGKJ genes were found.

Laminin-8 (alpha4beta1gamma1) is synthesized by lymphoid cells, promotes lymphocyte migration and costimulates T cell proliferation.

Laminins are a growing family of large heterotrimeric proteins with cell adhesive and signalling functions. They are major components of basement membranes and are found in many organs, including the vasculature and other compartments of bone marrow, thymus, lymph nodes and spleen. However, expression, recognition and use of laminin isoforms by lymphoid cells are poorly understood.

Monocytic cells synthesize, adhere to, and migrate on laminin-8 (alpha 4 beta 1 gamma 1).

Laminins, a growing family of large heterotrimeric proteins with cell adhesive and signaling properties, are major components of vascular and other basement membranes. Expression, recognition, and use of laminin isoforms by leukocytes are poorly understood. In monoblastic THP-1 cells, transcripts for laminin gamma(1)-, beta(1)-, and alpha(4)-chains were detected by RT-PCR.

Plasmodium falciparum AMA-1 erythrocyte binding peptides implicate AMA-1 as erythrocyte binding protein.

The role of AMA-1 during merozoite invasion has not yet been determined. However, reported experimental evidence suggests that this protein can be used, in particular as erythrocyte-binding protein, since, Fab fragments against this protein are able to block merozoite invasion. Using a previously described methodology, eight peptides with high binding activity to human erythrocyte, scattered along the different domains and having around 130 nM affinity constants, were identified in the Plasmodium falciparum AMA-1 protein.

Proteolytic processing of the Cyt1Ab1 toxin produced by Bacillus thuringiensis subsp. medellin.

Bacillus thuringiensis produces d-endotoxins that require proteolytic processing to become active. The activation of the B. thuringiensis subsp.

Plasmodium vivax: polymorphism in the merozoite surface protein 1 gene from wild Colombian isolates.

The Plasmodium vivax merozoite surface protein-1 (PvMSP-1) has been considered a candidate for a malaria vaccine against erythrocytic stages. PvMSP-1 is immunogenic during natural infections and exhibits antigenic polymorphism. The extent of genetic polymorphism in a region between the so-called interspecies conserved blocks (ICBs) 2 and 4 of the PvMSP-1 was analyzed in 20 isolates taken from patients from two different areas in Colombia.

Activation pattern and toxicity of the Cry11Bb1 toxin of Bacillus thuringiensis subsp. medellin.

Bacillus thuringiensis protoxins undergo proteolytic processing in the midgut of susceptible insects to become active. The ability to process the Cry11Bb1 protoxin by trypsin and Culex quinquefasciatus larval gut extracts was tested. The protease activity indicated by the appearance of proteolytic products increased with an increment in pH, with the highest activity being observed at pH 10.

Sequence and diversity of MHC DQA and DQB genes of the owl monkey Aotus nancymaae.

The New World primate Aotus nancymaae has been recommended by the World Health Organization (WHO) as a model for evaluation of malaria vaccine candidates, given its susceptibility to experimental infection with the human malaria parasites Plasmodium falciparum and Plasmodium vivax. We present here the nucleotide sequences of the complete cDNA of MHC-DQA1 and of the polymorphic exon 2 segments of MHC-DQB1/DQB2. In a group of three nonrelated animals captured in the wild, five alleles of MHC-DQA1 could be identified.

A GBP 130 derived peptide from Plasmodium falciparum binds to human erythrocytes and inhibits merozoite invasion in vitro.

The malarial GBP 130 protein binds weakly to intact human erythrocytes; the binding sites seem to be located in the repeat region and this region's antibodies block the merozoite invasion. A peptide from this region (residues from 701 to 720) which binds to human erythrocytes was identified. This peptide named 2220 did not bind to sialic acid; the binding site on human erythrocyte was affected by treatment with trypsin but not by chymotrypsin.

Serine repeat antigen peptides which bind specifically to red blood cells.

It has been reported that serine repeat antigen (SERA) binds directly to human erythrocyte membranes, inside-out vesicles and intact mouse erythrocytes. Similarly, mAbs specific against SERA are effective in blocking red blood cell (RBC) invasion by P. falciparum merozoites.

Chain specificity assignment of monoclonal antibodies to human laminins by using recombinant laminin beta1 and gamma1 chains.

In the present study, the chain specificity of 16 commonly used monoclonal antibodies to human laminin(s) was analysed by using recombinant laminin beta1 and gamma1 chains. By ELISA, all antibodies reacted with purified placenta laminin, and most antibodies recognised either recombinant beta1 or gamma1 chains. Reactivity and chain specificity was confirmed against the recombinant chains in Western blotting under non-reducing conditions, and only a few antibodies were reactive under reducing conditions.

Plasmodium falciparum: red blood cell binding studies of peptides derived from histidine-rich KAHRP-I, HRP-II and HRP-III proteins.

Histidine-rich proteins have been associated with Plasmodium falciparum infected red blood cells (RBC) cytoadherence, and RBC rosetting; these phenomena may cause clogging of the post-capillary venules, this being one of the main causes of severe cerebral malaria. They may also participate in parasite mature stages' evasion of the immune system and their subsequent destruction in the spleen. Non-overlapping synthetic peptides, corresponding to entire amino acid sequences reported for the KAHRP-I, HRP-II and HRP-III proteins, were used in RBC binding assays.

Plasmodium falciparum EBA-175 kDa protein peptides which bind to human red blood cells.

Solid experimental evidence indicates that EBA-175 is used as a ligand by the Plasmodium falciparum merozoite to bind to human RBC, via different binding processing fragments. Using synthetic peptides and specific receptor-ligand interaction methodology, we have identified 6 high-activity binding sequences from the EBA-175 CAMP strain; peptide 1758 (KSYGTPDNIDKNMSLIHKHN), located in the so-called region I for which no binding activity has been reported before, peptides 1779 (NIDRIYDKNLLMIKEHILAI) and 1783 (HRNKKNDKLYRDEWWKVIKK), located in region II, in a sub-region known as 5' Cys F2, previously reported as being a binding region, and peptides 1814 (DRNSNTLHLKDYRNEENERH), 1815 (YTNQNINISQERDLQKHGFH) and 1818 (NNNFNNIPSRYNLYDKKLDL), in region III-V where antibodies inhibit merozoite invasion of erythrocytes. The affinity constants were between 60 and 180 nM and the critical amino acids involved in the binding were identified.

Two MSA 2 peptides that bind to human red blood cells are relevant to Plasmodium falciparum merozoite invasion.

Plasmodium falciparum merozoite membrane surface antigen 2 (MSA2) has been associated with the development of protective immunity against malaria. MSA2 antibodies were able to inhibit in vitro merozoite invasion. In our search for experimental evidence concerning the participation of MSA2 in merozoite invasion, 40 peptides were synthesized according to sequences reported for the CAMP and FC27 prototype Plasmodium strains.

Isolation, characterization, molecular cloning and amplification of a species-specific M. leprae antigen.

A polyclonal serum sample from a lepromatous leprosy (LL) patient, which presented a specific recognition pattern for leprosin, was used to screen a Mycobacterium leprae genomic library constructed with DNA isolated from human lepromas. One clone, designated ML4-1, which expressed a specific antigenic determinant of M. leprae as part of a beta-galactosidase fusion protein, was isolated.

Decreased expression of interleukin-1alpha, interleukin-1beta, and cell adhesion molecules in muscle tissue following corticosteroid treatment in patients with polymyositis and dermatomyositis.

Objective: To study the effects of immunosuppressive therapy, in particular, corticosteroids, on morphologic signs of inflammation and expression of cytokines, adhesion molecules, and class I major histocompatibility complex (MHC) antigen in muscle tissue from patients with polymyositis (PM) and dermatomyositis (DM) and to correlate the molecular changes with changes in muscle function.

Methods: Seven patients with PM and 4 patients with DM underwent muscle biopsy before and after 3-6 months of therapy. Ten of the 11 patients were initially treated with prednisolone 30-60 mg/day.

Erythromegakaryocytic cells synthesize laminin-8 (alpha4beta1gamma1).

Blood platelets contain laminin-8 (alpha4beta1gamma1), a recently described laminin isoform, but the origin of platelet laminin is at present unknown. Laminin of platelets could be synthesized by megakaryocytes or, alternatively, endocytosed from plasma or other sources. In the present study, the synthesis and presence of laminin-8 in erythromegakaryocytic HEL and DAMI cells were explored.

Amino terminal peptides of the ring infected erythrocyte surface antigen of Plasmodium falciparum bind specifically to erythrocytes.

The Ring-Infected Erythrocyte Surface Antigen (Pf155/RESA) sequence was chemically synthesized in fifty four 20-mer sequential peptides, covering the entire protein, each of which was tested in erythrocyte binding assays. Peptides 6671 and 6673, corresponding to residues 141-160 and 181-200, respectively, presented a high specific binding activity to erythrocytes with affinity constants of 190 nM and 105 nM respectively. Their binding was sensitive to previous enzymatic treatment of erythrocytes.