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S Estrada-Parra

Publications and source records attributed to S Estrada-Parra.

At least 19 recordsLinked to original sources
PubMed1992

Use of synthetic peptides corresponding to sequences of Mycobacterium leprae proteins to study delayed-type hypersensitivity response in sensitized guinea pigs.

In this work we report the synthesis of 10 peptides (P1-P10) corresponding to one or several segments of the amino acid sequence of proteins from Mycobacterium leprae: 65 kDa, 28 kDa, 18 kDa, and 28 kDa superoxide dismutase, recently renamed antigens 2L, 9L, 12L, and 14L, respectively. They were assayed in the guinea pig model for the induction of a delayed-type hypersensitivity response in M. leprae and BCG-sensitized animals. To sensitize the animals two schemes were used: either a single dose of 5 x 10(9) irradiated or autoclaved whole bacilli, or four weekly intramuscular injections each containing 500 micrograms of soluble extract of M. leprae (MLSE) in incomplete Freund's adjuvant. Because the second scheme used far too much antigen, we decided to use the first scheme for the experiments we report here. DTH reactions of sensitized animals were induced after 30 days with intradermal injections of 5 micrograms of MLSE and with each of the 10 peptides at three different concentrations: 250 micrograms, 100 micrograms, and 0.05 micrograms. All M. leprae-sensitized guinea pigs gave indurations of 10 mm or more with MLSE, which indicates that the animals were sensitized. None of them gave DTH indurations with 250 micrograms or 100 micrograms, but some of them had positive DTH reactions with the 0.05 micrograms doses of the synthetic peptides. This is most likely due to the fact that we have used an outbred strain of guinea pigs. The peptides were also tested at 0.05 micrograms in animals sensitized with BCG. P7 and P10 seem to be nonspecific peptides; the remaining peptides only induced DTH in the M. leprae-sensitized guinea pigs. P3 (segments 65-85 of the 65-kDa protein) induced a positive DTH in 58% of the tested animals. In other experiments, guinea pigs were sensitized with a single injection (500 micrograms) of each of the synthetic peptides. All animals, except those sensitized with P4 and P8, had positive DTH responses when the homologous peptide was used. Those sensitized with P2, P4, P5, P7, and P8 were able to produce indurations when MLSE was used for the induction of the DTH reaction.

Amino Acid Sequence↗
PubMed1985

Biochemical alterations in the serum of armadillos (Dasypus novemcinctus) infected with Mycobacterium leprae. A preliminary report.

Armadillos (Dasypus novemcinctus) were inoculated with Mycobacterium leprae isolated from lepromas taken from untreated lepromatous patients or from the spleen of an armadillo previously infected with human M. leprae. The effect of the infection on the serum levels of lactic dehydrogenase (LDH), alkaline phosphatase (AlkP), glutamate-oxalacetate (GOT) and glutamate-pyruvate (GPT) transaminases was investigated. In general, there was a good correlation between positive evidences of infection and alterations in the levels of LDH, GOT, and GPT. Although elevations in LDH levels were more striking, elevations in GOT and GPT levels were more consistent with the disease. When an absolute increase in the total LDH activity was not observed in a M. leprae-infected animal, an increase in the level of LDH isozyme V was still clearly evident. Serum levels of alkaline phosphatase were not affected by the disease. The ratio GOT/GPT (greater than 1.0) in the infected animals reflected and supported the chronic nature of the disease and the liver involvement. The enzymatic alterations are not, however, specific for leprosy.

Alanine Transaminase↗
PubMed1976

Immunochemical characterization of the anti-RNA antibodies found in scleroderma and systemic lupus erythematosus. II. Reactivity with hsa-coupled, uridine-containing, monophosphoric ribodinucleotides.

Sera from patients with scleroderma have been found to have anti-RNA antibodies which react with human serum albumin (HSA)-coupled uridine and uridine monophosphate (UMP) and are inhibited by uracil, uridine and UMP. Scleroderma sera react uniformly with 5'-polyuridylic acid (poly(U)) and fail to react with polyadenylic, polyuridylic acid poly(A) - poly(U)) which is also indicative of their uracil specificity. Anti-RNA antibodies found in systemic lupus erythematosus (SLE) are immunochemically different from those found in scleroderma in that, instead of being uniformly specific to uracil, they are markedly heterogeneous and may react with uracil, uridine and/or UMP. SLE sera frequently react with poly(A) - poly(U), indicating also their ability to recognize the double helical structure of double-stranded RNA. Thirty-seven scleroderma and thirty-four SLE sera from as many patients with either of these conditions were tested against HSA-coupled, uridine-containing monophosphoric dinucleotides in an attempt to characterize further their anti-RNA antibodies. Scleroderma sera were found to react primarily with dinucleotides in which uridine was the base proximal to the carrier protein and, except for sera that also contained antibodies to adenosine which reacted with UpA, they failed to react with dinucleotides in which uridine was in a terminal position only. Reaction with dinucleotides in which uridine was proximal to the carrier protein could be inhibited by uracil but not by the corresponding terminal base. Some lupus sera were found to react with both dinucleotides that contain the same bases in opposite sequence, e.g. ApU and UpA, while others were found to react with only one of the sequences. They were also found to react more frequently with dinucleotides in which HSA was coupled to a base other than uridine, suggesting that the reaction is primarily due to anti-DNA antibodies. Because immunization with dinucleotides coupled to protein prepared by the same method we have used, yields higher specificity to the base attached to the carrier protein, our findings suggest that, in scleroderma, a single event, akin to that of immunization with a purified antigen, gives rise to the anti-RNA antibodies, whereas in systemic lupus erythematosus there is a considerably wider immunological aberration.

Adenosine↗
PubMed1975

Uracil-specific anti-R.N.A. antibodies in scleroderma.

Antibodies to single-stranded R.N.A. were found by counter immunoelectrophoresis in all of 40 sera from patients with scleroderma. These antibodies were specific to the uracil bases of R.N.A. Antibodies to R.N.A. were also found in 20 of 40 sera from patients with systemic lupus erythematosus (S.L.E.), but in none of forty controls. Antibodies to R.N.A. found in S.L.E. sera could be differentiated immunochemically from those found in scleroderma in that they were more heterogeneous and could react selectively with either uridine or uridine monophosphate. Antibodies ot D.N.A. were more frequent in S.L.E. than in scleroderma. That antibodies to D.N.A. are actually present in scleroderma and precipitin lines are not the result of cross reactivity with anti-R.N.A. antibodies is indicated by the finding that 10 of the 18 scleroderma sera which reacted with D.N.A. also reacted with thymidine, a base present in D.N.A. but not in R.N.A.

Adenosine↗
PubMed1975

The heterogeneity of anti-DNA antibodies in systemic lupus erythematosus and other diseases.

The antigenic specificities of antinucleic acid antibodies occurring in systemic lupus erythematosus (SLE), chronic active liver disease, and progressive systemic sclerosis (PSS) have been studied by means of haptenic nucleosides and nucleotides coupled to human serum albumin. SLE sera were also tested with dinucleotides. SLE and chronic active liver disease sera showed marked heterogeneity, producing precipitin lines with nucleosides or nucleotides, or both. The reaction might occur with a nucleoside and not with the corresponding nucleotide, or vice versa. The SLE sera reacted to dinucleotides with marked specificity, being able to recognize base sequences or to react with a dinucleotide despite the absence of a reaction with the individual bases. All sera from patients with PSS showed precipitins with RNA, uridine and UMP. PSS sera which reacted with a nucleoside also reacted with the corresponding nucleotide. Antibodies to DNA were found in a smaller proportion of PSS sera than in sera from SLE or chronic active liver disease. Their presence was confirmed by reactivity with thymidine and TMP.

Antibodies, Anti-Idiotypic↗