Biomedical subjects

W E Müller

Publications and source records attributed to W E Müller.

At least 109 records · Page 6Linked to original sources

PubMed1999

Piracetam reverses hippocampal membrane alterations in Alzheimer's disease.

The in vitro effects of piracetam treatment on the fluidity of membranes from the hippocampus of Alzheimer's Disease patients (AD) and non-demented controls were studied. Hippocampal membranes of AD patients showed a significant lower hydrocarbon core fluidity compared with membranes from elderly non-demented controls. Preincubation with piracetam enhanced the hydrocarbon core fluidity of hippocampal membranes from AD-patients as well as elderly controls in a concentration depending fashion, although the effect was more pronounced for the AD membranes. In the presence of piracetam, the difference of the membrane fluidity between AD and control membranes was not longer apparent.

Alzheimer Disease↗

PubMed1999

Origin of the integrin-mediated signal transduction. Functional studies with cell cultures from the sponge Suberites domuncula.

Sponges (phylum Porifera) represent the phylogenetically oldest metazoan animals. Recently, from the marine sponge Geodia cydonium a first cDNA encoding a putative integrin receptor molecule was isolated. In the present study basic functional experiments have been conducted to test the hypothesis that in sponges integrin polypeptides also function as adhesion molecules and as outside-in signaling molecules. The sponge Suberites domuncula has been used for the experiments because from this sponge only has a cell culture been established. Here we report that aggregation factor (AF)-mediated cell-cell adhesion is blocked by the RGDS peptide which is known to interact with beta integrin. Both RGDS and AF were found to stimulate DNA synthesis within 24 h. The beta subunit of the integrin receptor was cloned from S. domuncula; the estimated 91-kDa molecule comprises the characteristic signatures. Evolutionary conservation of the beta integrin was assessed by comparison with corresponding beta integrin subunits from evolutionary higher metazoan taxa. Addition of RGDS or of AF to isolated cells of S. domuncula causes a rapid (within 1-2 min) increase in the intracellular Ca2+ concentration which is further augmented in the presence of Ca2+. Furthermore, incubation of the cells with RGDS or AF causes an activation of the GTP-binding protein Ras. In addition it is shown that after a prolonged incubation of the cells with RGDS and AF the expression of the genes coding for Ras and for calmodulin is upregulated. These results suggest that the integrin receptor functions in the sponge system not only as adhesion molecule but also as a molecule involved in outside-in signaling.

Amino Acid Sequence↗

PubMed1999

A homolog of the putative tumor suppressor QM in the sponge Suberites domuncula: downregulation during the transition from immortal to mortal (apoptotic) cells.

The activation of components of the transcription factors such as AP-1 or c-jun is essential for a physiological response of metazoan cells during aging. The activity of such proto-oncoproteins is under enzymatic control. The function of c-jun is additionally modulated by the QM protein. Here, we studied the expression of the gene, encoding the QM-like protein in the sponge Suberites domuncula. These animals contain high levels of telomerase in their somatic cells. To understand the switch from telomerase-positive immortal cells to telomerase-negative mortal cells which undergo apoptosis, the expression of the QM-like gene was measured in this system. The cDNA, termed QMSD, encoding the QM-like protein was isolated from S. domuncula; its 642 bp long open reading frame encodes a putative protein, QM-SUBDO, of 24,702 Da. Phylogenetic analysis of the sponge QM-like protein revealed that it is closely related to other metazoan QM polypeptides and distinct from sequences of Eumycota or Viridiplantae. Our investigations demonstrated that in gemmules as well as in untreated tissue the expression of the QM-like gene is significantly higher than in tissue which undergoes induced apoptosis. The level of the QM-like protein even decreases drastically in cells that are induced to apoptosis (e.g. by cadmium). We suggest therefore that one event that is involved in the transition of sponge cells from their immortal telomerase-positive to the mortal telomerase-negative state may be the downregulation of the QM-like protein, a putative tumor suppressor polypeptide.

Amino Acid Sequence↗

PubMed1999

Piracetam: novelty in a unique mode of action.

Extensive research of the recent years has demonstrated that piracetam is effective in the treatment of cognitive decline in aging and dementia. It is usually much more active in situations of impaired brain function. Accordingly, its mechanism of action has been associated with neurochemical deficits of the aged brain relevant to cognitive dysfunctions. Since many of these neurochemical deficits depend on changes of membrane properties, including fluidity, it is of special importance that piracetam not only modifies membrane properties by interacting with the polar head moieties of the phospholipid bilayer, but also that this effect is more pronounced in membranes of aged as opposed to young animal and human brains, and that this mechanism also has specific relevance for brain membranes of Alzheimer's disease patients. Altering membrane properties might also be involved in vascular effects of piracetam such as improved erythrocyte deformability and normalization of hyperactive platelet aggregation. This novel mechanism of piracetam thus combines a rather non-specific physico-chemical mode of action with the pharmacological and clinical experience with this unique drug - effects are always much more pronounced when function is impaired.

Aged↗

PubMed1999

Piracetam improves cognitive performance by restoring neurochemical deficits of the aged rat brain.

In order to test the hypothesis that piracetam improves cognitive functions by restoring biochemical deficits of the aging brain, we investigated the effects of piracetam treatment (300 mg/kg daily for 6 weeks) on the active avoidance performance of young and aged rats. After testing, the rats were killed and membrane fluidity and NMDA as well muscarinic cholinergic receptor densities were determined in the frontal cortex, the hippocampus, the striatum, as well as the cerebellum. Piracetam treatment improved active avoidance learning in the aged rats only and elevated membrane fluidity in all brain regions except the cerebellum in the aged animals. Moreover, we observed a positive effect of piracetam treatment on NMDA receptor density in the hippocampus and on muscarinic cholinergic receptor densities in the frontal cortex and the striatum and to a lesser extent in the hippocampus. Again, these effects were only observed in aged animals. Discrimination analysis indicated that piracetam effects on membrane fluidity in the frontal cortex, the hippocampus, and the striatum and its effects on NMDA densities in the hippocampus might be involved in its positive effects on cognitive performance.

Age Factors↗

PubMed1999

Increased gene expression of a cytokine-related molecule and profilin after activation of Suberites domuncula cells with xenogeneic sponge molecule(s).

Porifera (sponges) constitute the lowest metazoan phylum. Experiments examined whether sponges can recognize self/nonself molecules. Cells from the marine sponge Suberites domuncula were incubated with membranes from either S. domuncula or another marine sponge, Geodia cydonium, as well as with recombinant alpha-integrin from G. cydonium. The cells responded immediately with a rise of intracellular Ca2+ ([Ca2+i]) if they were treated with membranes from G. cydonium but not after treatment by those from S. domuncula. This change of [Ca2+i] was also recorded with G. cydonium alpha-integrin. In parallel, the expression of two genes was strongly upregulated; one codes for a cytokine-related molecule, pre-B-cell colony-enhancing factor, and the other for profilin. These genes have previously been found to be highly expressed in human or echinoderm cells in the presence of xenogeneic proteins. Our data support the hypothesis that a primordial immune response system is present in sponges.

Amino Acid Sequence↗

PubMed1999

Differential expression of allograft inflammatory factor 1 and of glutathione peroxidase during auto- and allograft response in marine sponges.

Very recently, Porifera (sponges) have been proven to be suitable model systems to study auto- and allograft recognition at the molecular level. Several potential immune molecules have been isolated from the marine sponges Suberites domuncula and Geodia cydonium, among them those which comprise Ig-like domains in their extracellular part. Here we report on the isolation of two cDNAs from S. domuncula that code for molecules involved in mammals in cytokine-mediated graft response; a putative allograft inflammatory factor 1 (AIF-1) and a non-selenium glutathione peroxidase (GPX). Both polypeptides share high similarity with the corresponding mammalian proteins. The expression of the two genes during auto- and allograft recognition in S. domuncula and G. cydonium was determined. It is shown that the expression of the AIF-1-related gene is upregulated only in allografts, while the GPX-related gene is expressed in the fusion zones formed between auto- as well as allografts. Taken together, these findings suggest that besides cell-mediated defense reactions a cytokine-dependent immune response is also elicited during graft recognition in sponges.

Amino Acid Sequence↗

PubMed1999

Origin of insulin receptor-like tyrosine kinases in marine sponges.

One autapomorphic character restricted to all Metazoa including Porifera [sponges] is the existence of transmembrane receptor tyrosine kinases (RTKs). In this study we screened for molecules from one subfamily within the superfamily of the insulin receptors. The subfamily includes the insulin receptors (InsR), the insulin-like growth factor I receptors, and the InsR-related receptors--all found in vertebrates--as well as the InsR-homolog from Drosophila melanogaster. cDNAs encoding putative InsRs were isolated from the hexactinellid sponge Aphrocallistes vastus, the demosponge Suberites domuncula, and the calcareous sponge Sycon raphanus. Phylogenetic analyses of the catalytic domains of the putative RTKs showed that the sponge polypeptides must be grouped with the InsRs. The relationships revealed that all sponge sequences fall into one branch of this group, whereas related sequences from mammals (human, mouse, and rat), insects and molluscs, and polypeptides from one cephalochordate, fall together into a second branch. We have concluded that (i) the InsR-like molecules evolved in sponges prior to the "Cambrian Explosion" and contributed to the rapid appearance of the higher metazoan phyla; (ii) the sponges constitute a monophyletic taxon, and (iii) epidermal growth factor (EGF)-like domains are present in sponges, which allows the insertion of this domain into potential receptor and matrix molecules.

Amino Acid Sequence↗

PubMed1999

Suppression of PrP(Sc)- and HIV-1 gp120 induced neuronal cell death by sulfated colominic acid.

The scrapie prion protein (PrP(Sc)) has been shown to induce apoptosis of rat cortical neurons in vitro. Here we demonstrate that the toxic effect displayed by PrP(Sc) can be blocked by sulfated colominic acid (polymer of N-acetylneuraminic acid). This compound acts neuroprotectively at a concentration of > or = 0.3 microg/ml when preincubated with the neurons or PrP(Sc). Rat cortical cells also undergo apoptosis after incubation with the HIV-1 coat protein gpl20 in vitro. This effect was abolished also by sulfated colominic acid when preincubated with the cells or gpl20. Addition of 0.3 microg/ml of compound resulted in an increase in cell viability by about 1.6-1.9-fold compared to cultures incubated for 18 h with 30 ng/ml of PrP(Sc) or 20 ng/ml of gpl20 alone (containing about 40% viable cells). Sulfated colominic acid does not act as antagonist of NMDA receptor channels at concentrations of up to 3 microg/ml when co-administered with 100 microg/ml of NMDA. It displayed a strong cytoprotective effect on human T lymphoblastoid CEM cells exposed to HIV-1; a 50% protection occurred after preincubation of the cells with 0.43 microg/ml of compound. At the same concentration, the compound caused an inhibition of HIV-1-induced syncytium formation. Sulfated colominic acid may be a promising compound for treatment of dementia caused by PrP(Sc) and HIV-1 infections.

Animals↗

PubMed1999

Increased expression of integrin and receptor tyrosine kinase genes during autograft fusion in the sponge Geodia cydonium.

Recently cDNAs coding for cell surface molecules have been isolated from sponges. The molecules for alpha-integrin, galectin, and receptor tyrosine kinase (RTK), obtained from the marine sponge, Geodia cydonium, have been described earlier. In the present study also the cDNA for one putative beta-integrin has been identified from G. cydonium. The deduced aa sequence comprises the characteristic signatures, found in other metazoan beta-integrin molecules; the estimated size is 95,215 Da. To obtain first insights into the molecular events which proceed during autograft fusion, the expressions of these genes were determined on transcriptional and translational level. The cDNAs as well as antibodies raised against the recombinant sponge proteins alpha-integrin, RTK and galectin were used and Northern blot experiments and immunocytochemical analyses have been performed. The results show that transcription of the two subunits of an integrin receptor as well as of the RTK are strongly upregulated after grafting; levels of > 10-fold have been determined in the fusion zone of the grafts after a 10 days incubation. Immunofluorescence studies of sections through the fusion zone support these data. In contrast the transcription of the gene encoding galectin is drastically downregulated after grafting. In a parallel series of experiments the level of the heat-shock protein-70 was determined and it was found that it remained unchanged after grafting. We conclude that integrin subunits and the RTK molecule are involved in self-self recognition of sponge.

Amino Acid Sequence↗

PubMed1999

Assessment of DNA damage and repair in human peripheral blood mononuclear cells using a novel DNA unwinding technique.

A newly developed, fast and sensitive microplate assay (Fast Micromethod) was used for the assessment of gamma-radiation-induced DNA damage in peripheral blood mononuclear cells (PBMC) from healthy donors of various ages and from cancer patients undergoing radiotherapy. This assay detects the presence of DNA single-strand breaks and alkali-labile sites by monitoring the rate of DNA unwinding under alkaline conditions using the fluorescent dye PicoGreen, which preferentially binds to double-stranded DNA at high pH (>12.0); it requires only minimal amounts of material (approximately 3 x 10(3) cells/well) and can be performed within 3 hrs. or less. EDTA blood samples were collected from patients not undergoing chemotherapy prior and immediately after irradiation, or were collected from healthy donors and irradiated ex vivo. The results revealed that the amount of DNA strand breaks in PBMC, induced by application of a single dose to patients in the course of radiotherapy treatment, markedly varied between different individuals. To examine the effect of age on DNA damage, the basal levels of DNA damage in PBMC from a total of 30 healthy donors were determined: 10 were 20 to 30 years of age, 10 were 40 to 60 years of age and 10 were >70 years of age. It was found that the mean basal level of DNA damage from donors in the >70-year age group was significantly higher (by 97%) than that of the 20- to 30-year age group and 27% higher than that of the 40- to 60-year age group. Measurements of the level of induced DNA damage in PBMC isolated from blood after 2 Gy irradiation with 60Co gamma-rays revealed no significant differences between donors aged 20-30 and 40-60. However, there was a strong increase (by 2.3- to 2.9-fold) in radiosensitivity in the age group >70. The microplate assay described may be used as a pretherapeutic sensitivity test for the assessment of the individual radiosensitivity of patients prior to radiation therapy.

Adult↗

PubMed1999

Hyperforin, a major antidepressant constituent of St. John's Wort, inhibits serotonin uptake by elevating free intracellular Na+1.

Extracts of Hypericum perforatum (St. John's Wort) are widely used for the treatment of depressive disorders and are unspecific inhibitors of the neuronal uptake of several neurotransmitters. Previous studies have shown that hyperforin represents the reuptake inhibiting constituent. To characterize the mechanism of serotonin reuptake inhibition, kinetic analyses in synaptosomes of mouse brain were performed. Michaelis-Menten kinetics revealed that hyperforin (2 microM) induces a decrease in V(max) by more than 50% while only slightly decreasing K(m), indicating mainly noncompetitive inhibition. By contrast, citalopram (1 nM) leads to an elevation of K(m) without changing V(max). Monensin, a Na(+)/H(+) exchanger, showed similar properties as hyperforin (decrease of V(max) without changing K(m)). Compared with classical antidepressants, such as selective serotonin reuptake inhibitors and tricyclic antidepressants, hyperforin is only a weak inhibitor of [(3)H]paroxetine binding relative to its effects on serotonin uptake. As monensin decreases serotonin uptake by increasing Na(+)/H(+) exchange, we compared the effects of hyperforin and monensin on the free intracellular sodium concentration ([Na(+)](i)) in platelets by measuring 1,3-benzenedicarboxylic acid, 4,4'-[1,4,10-trioxa-7, 13-diazacyclopentadecan-7,13-diylbis(5-methoxy-6, 2-benzofurandiyl)]bis-, tetraammonium salt (SBFI/AM) fluorescence. Both drugs elevated [Na(+)](i) over basal levels, with a maximal [Na(+)](i) of 69 +/- 16.1 mM (50 microM hyperforin) and 140 +/- 9.1 mM (10 microM monensin). Citalopram at concentrations relevant for [(3)H]serotonin uptake inhibition had no effect on [Na(+)](i). Although the mode of action of hyperforin seems to be associated with elevated [Na(+)](i) similar to those levels found with monensin, the molecular mechanism might be different, as even at high concentrations, hyperforin does not elevate free intracellular sodium concentration ([Na(+)](i)) up to the extracellular level, as monensin does. Hyperforin represents the first substance with a known preclinical antidepressant profile that inhibits serotonin uptake by elevating [Na(+)](i).

Animals↗

PubMed1999

Receptor tyrosine kinase, an autapomorphic character of metazoa: identification in marine sponges.

In the present review we summarize sequence data obtained from cloning of sponge receptor tyrosine kinases [RTK]. The cDNA sequences were mainly obtained from the marine sponge Geodia cydonium. RTKs (i) with immunoglobulin [Ig]-like domains in the extracellular region, (ii) of the type of insulin-like receptors, as well as (iii) RTKs with one extracellular speract domain, have been identified. The analyses revealed that the RTK genes are constructed in blocks [domains], suggesting a blockwise evolution. The phylogenetic relationships of the sequences obtained revealed that all sponge sequences fall into one branch of the evolutionary tree, while related sequences from higher Metazoa, human, mouse and rat, including also invertebrate sequences, together form a second branch. It is concluded that the RTK molecules have evolved in sponges prior to the "Cambrian Explosion" and have contributed to the rapid appearance of the higher metazoan phyla and that sponges are, as a taxon, also monophyletic. Due to the fact that protein tyrosine kinases in general and RTKs in particular have only been identified in Metazoa, they are, as a group qualified, to be considered as an autapomorphic character of all metazoan phyla.

Amino Acid Sequence↗

PubMed1998

Effect of flupirtine on cell death of human umbilical vein endothelial cells induced by reactive oxygen species.

Flupirtine (KATADOLON), known as a nonopiate centrally acting analgesic drug, was tested as to its potential to prevent apoptosis of human endothelial cells induced by reactive oxygen species (ROS). It was found that Flupirtine displayed no effect on viability and cell proliferation of human umbilical vein endothelial cells (HUVEC) up to a concentration of 10 microg/mL. Apoptosis, induced by ROS and generated by hypoxanthine/xanthine oxidase (EC 1.1.3.22) (HX/XOD) or t-butyl hydroperoxide, was reduced after preincubation with Flupirtine for 3 hr by 35% and 41%, respectively. The maximal cytoprotective effect against apoptosis was observed at a drug concentration of 1 to 3 microg/mL. Flow cytometric studies revealed that Flupirtine was able to decrease the number of necrotic cells as well as of apoptotic cells. Neither the simultaneous administration of Flupirtine with the apoptosis-inducing agent nor the preincubation of HUVEC with Flupirtine influenced the increase in the intracellular Ca2+ concentration [Ca2+]i caused by the production of ROS.

Aminopyridines↗

PubMed1998

Expression of the human XPB/ERCC-3 excision repair gene-homolog in the sponge Geodia cydonium after exposure to ultraviolet radiation.

The marine demosponge Geodia cydonium encodes a gene, termed GCXPB, which displays 62% identity to the human XPB/ERCC-3 gene that specifically corrects the repair defect in xeroderma pigmentosum and in Cockayne's syndrome. The cDNA was isolated and characterized the deduced aa sequence, XPB_GEOCY, with the calculated size of 91,541 Da comprises the characteristic domains found in the related helicases. Phylogenetic tree analysis revealed that the sponge sequence is grouped to the metazoan related XPB/ERCC-3 polypeptides. Northern Blot analyses have been performed with sponge samples collected at different depths, thus exposed to different intensities of UV sunlight in the field. The intensity of the 2.6 kb band, corresponding to the transcripts of the sponge GCXPB gene was highest in those biotopes, which are closer to the surface of the sea, lower were the expressions in animals from a cave or from depths of 22 to 35 m. Controlled laboratory studies revealed that after irradiation of specimens with 300 or 1000 J/m2 UVB light a dose-dependent increase of the steady-state level of GCXPB occurs, values up to 29-fold with respect to the controls which were kept in the dark have been determined. In parallel, the DNA integrity in the sponge samples was measured using the sensitive Fast Micromethod assay. The data revealed that the degree of strand DNA breaks paralleled the increase of expression of the GCXPB gene. From these data it is concluded that the XPB/ERCC-3-like gene in the sponge G. cydonium is UV light-inducible and hence might be used as biomarker for UV light exposure in the field.

Amino Acid Sequence↗

PubMed1998

Sarcophytolide: a new neuroprotective compound from the soft coral Sarcophyton glaucum.

Bioactivity-guided fractionation of an alcohol extract of the soft coral Sarcophyton glaucum collected from the intertidal areas and the fringing coral reefs near Hurghada, Red Sea, Egypt resulted in the isolation of a new lactone cembrane diterpene, sarcophytolide. The structure of this compound was deduced from its spectroscopic data and by comparison of the spectral data with those of known closely related cembrane-type compounds. In antimicrobial assays, the isolated compound exhibited a good activity towards Staphylococcus aureus, Pseudomonas aeruginosa, and Saccharomyces cerevisiae. Sarcophytolide was found to display a strong cytoprotective effect against glutamate-induced neurotoxicity in primary cortical cells from rat embryos. Preincubation of the neurons with 1 or 10 microg/ml of sarcophytolide resulted in a significant increase of the percentage of viable cells from 33 +/- 4% (treatment of the cells with glutamate only) to 44 +/- 4 and 92 +/- 6%, respectively. Administration of sarcophytolide during the post-incubation period following glutamate treatment did not prevent neuronal cell death. Pretreatment of the cells with sarcophytolide for 30 min significantly suppressed the glutamate-caused increase in the intracellular Ca2+ level ([Ca2+]i). Evidence is presented that the neuroprotective effect of sarcophytolide against glutamate may be partially due to an increased expression of the proto-oncogene bcl-2. The coral secondary metabolite, sarcophytolide, might be of interest as a potential drug for treatment of neurodegenerative disorders.

Animals↗

PubMed1998

Identification of the reaction products of (2'-5')oligoadenylate synthetase in the marine sponge.

Previously we reported on the presence of a high (2'-5')oligoadenylate synthetase activity in the marine sponge Geodia cydonium [Kuusksalu, A., Pihlak, A., Müller, W. E. G. & Kelve, M. (1995) Eur. J. Biochem. 232, 351-357]. The presence of (2'-5')oligoadenylates [(2'-5')A] in crude sponge extract was shown by radioimmunoassay and by their HPLC comigration with authentic (2'-5')A oligomers. In addition, the sponge (2'-5')oligoadenylates displayed biological activity, as determined by inhibition studies of protein biosynthesis in rabbit reticulocyte lysate. In the present study individual (2'-5')oligoadenylates synthesized by sponge enzyme were separated by HPLC. The exact composition of every oligonucleotide peak eluted was determined by matrix-assisted laser-desorption-ionization mass spectrometry (MALDI-MS) analysis. The 2'-5' phosphodiester bond in oligoadenylates was verified by NMR analysis. Based on the high concentration of (2'-5')A oligomers in G. cydonium and their similarity with those found in mammals we propose that the (2'-5')A system is involved in a cytokine-mediated pathway and/or in a protection system against viruses, present in the marine environment.

2',5'-Oligoadenylate Synthetase↗

PubMed1998

Putative multiadhesive protein from the marine sponge Geodia cydonium: cloning of the cDNA encoding a fibronectin-, an SRCR-, and a complement control protein module.

Sponges (Porifera) representing the simplest metazoan phylum so far have been thought to possess no basal lamina tissue structures. One major extracellular matrix protein that is also a constitutive glycoprotein of the basal lamina is fibronectin. It was the aim of the present study to identify the native protein from the marine sponge Geodia cydonium and to isolate the corresponding cDNA. In crude extracts from this sponge protein(s) of M(r) of approximately 230 and approximately 210 kDa could be visualized by Western-blotting using an anti-fibronectin [human] antibody. By PCR cloning from a cDNA library of G. cydonium we isolated a cDNA comprising one element of fibronectin, the type-III (FN3) module. The cDNA (2.3 kb long), encoding a 701 amino acid [aa] long putative "multiadhesive protein" termed MAP_GEOCY, was found to contain (i) a fibronectin-, (ii) a scavenger receptor cysteine-rich [SRCR]-, and (iii) a short consensus repeat [SCR] module. The 89 aa long fibronectin module comprises the characteristic topology and conserved aa found in fibronectin type-III (FN3) elements. The SRCR module (101 aa) features the characteristics of group B SRCR molecules. The predominant proteins belonging to this group are the mammalian WC1-, M130-, CD6- and CD5 antigens that probably are involved in immunological reactions. The SCR module (54 aa) shows the characteristics of type III SCR modules found in complement receptors. Phylogenetic analyses performed with all three building blocks of the "multiadhesive protein" showed that the respective sponge modules form independent, possibly basal, lineages in trees that include the corresponding modules from higher metazoan animals. In summary, these data demonstrate for the first time that the phylogenetically oldest Metazoa, the sponges, contain protein modules seen in higher animals in proteins of the extracellular matrix and in molecules involved in cell-mediated immune reactions in vertebrates.

Amino Acid Sequence↗