Antigenic variability in Trichuris trichiura populations.

The present study examines antigenic variability for the human whipworm Trichuris trichiura. Recognition by IgG of somatic antigens of individual worms collected from 3 intensely infected children from Jamaica, West Indies has been investigated by immunoblotting. When probed with 1 plasma sample, significant differences in recognition of 2 selected antigens among worm populations and between male and female worms was observed. In addition, there was evidence for antigenic variability within worm populations at the individual worm level. Such variation may have considerable implications for the development of immunity to parasitic nematodes.

Antigenic variability in trichuris trichiura populations

The present study examines antigenic variability for the human whipworm Trichuris trichiura. Recognition by IgG of somatic antigens of individual worms collected from 3 intensely infected children from Jamaica, West Indies has been investigated by immunoblotting. When probed with 1 plasma sample, significant differences in recognition of 2 selected antigens among worm populations and between male and female worms was observed. In addition, there was evidence for antigenic variability within worm populations at the individual worm level. Such variations may have considerable implications for the development of immunity to parasitic nematodes.(AU)

High resolution two-dimensional polyacrylamide gel electrophoresis of cerebrospinal fluid in patients with neurological diseases.

The protein pattern of cerebrospinal fluid (CSF) of 334 patients with various neurological and systemic diseases was investigated by high resolution two-dimensional electrophoresis (2-DE). 2-DE gels of normal CSF contain proteins which are not detectable in 2-DE gels of serum. Disturbances of the blood-brain or blood-CSF barrier, and degenerative diseases of the brain and malignant diseases produce specific changes on 2-DE gels of the CSF. The appearance of 10 spot areas in the light chain region of 2-DE gels seem to be connected with the diagnosis of multiple sclerosis. The sensitivity and the specificity of these spot areas for the diagnosis of multiple sclerosis are described. Proteins within the ten spot areas are immunoglobulin light chains or substances which cross-react very strongly with light chain antibodies as demonstrated by immunoblotting and immunoabsorption.

Two-dimensional electrophoresis of proteins in tumours of the lung.

The proteins of solid lung tumours (15 adenocarcinomas and 10 squamous cell carcinomas) were examined by high resolution two-dimensional electrophoresis (2-DE) and compared with the proteins of adjacent lung tissue which demonstrated no histological evidence of malignant transformation, and with the proteins of other malignant tumours and normal tissues. To investigate tumour cell-specific protein synthesis, we isolated malignant and normal cells enzymatically with collagenase, elastase, and DNase. Tissue and tumour cells were enriched in an additional step on a Percoll gradient. The 2-DE gel patterns derived from entire tissue and enriched tissue cell preparations were compared. No specific differences were found between the 2-DE protein patterns from adenocarcinomas and squamous cell carcinomas of the lung, but three proteins identified on the 2-DE gels appeared to be tumour-associated. Spot A is present in non-neoplastic and neoplastic epithelial tissues. Spot B is pronounced in 2-DE gels of sarcomas, but is also present in preparations of other malignant tissues. Spot C is present in all malignant cell preparations. These three spots were also demonstrated in 2-DE protein patterns from tissue cultures of malignant cell lines. Spot B and spot C were also present in some normal tissues.

S-phase detection with an antibody to bromodeoxyuridine. Role of DNase pretreatment.

We have previously described a monoclonal antibody (BU-1) to 5-bromo-2-deoxyuridine (BrdUrd) that is useful for measurement of cell cycle S-phase. BU-1 hybridoma supernatant reacted with incorporated BrdUrd after the cells had been ethanol fixed; without a requirement for acid or base denaturation. We have found that this reactivity is lost if purified antibody is used, if the culture supernatants are heated, or if a mycoplasma-free hybridoma line is isolated. The supernatant contained endogenous DNase activity that was a result of mycoplasma infection of the cell line. This DNase activity was required for staining the cells with BU-1 in the absence of other denaturation steps. The endogenous DNase could be substituted for by the addition of bovine pancreatic DNase I. The disruption of the double stranded DNA structure with an enzyme rather than with harsh chemical or heat treatments does not affect protein structure or cellular morphology and allows the detection of incorporated BrdUrd of morphologic or antigenic cell subsets. DNase pre-treatment may also be useful for detection of other 'hidden' DNA antigens.

Two-dimensional gel electrophoresis of serum specimens from patients with monoclonal gammopathies.

We modified the ISO-DALT two-dimensional gel electrophoresis system to allow the routine examination of serum specimens from patients with monoclonal gammopathies. This system, MC-Iso 1, is characterized by a broad pH gradient for resolving the basic immunoglobulin heavy and light chains. The increased resolution of basic proteins may be explained on theoretical grounds by an increase in voltage in this region of the cell. Ancillary techniques, such as those for albumin removal and pI assignment through use of charge standards, have also been implemented. The locations of immunoglobulin heavy chains have been confirmed by examination of over 250 serum samples as well as by "electro-blotting," with use of specific antisera. IgG subclass may also be predicted by location, but not with perfect accuracy. Differentiation of kappa and lambda light chains by relative mobility has been examined; the predictive value for correct identification of kappa chains is 83%, that for lambda chains 69%. Several unknown proteins have been observed in macroglobulinemia, related to mu heavy chain. Finally, we have determined that there is excellent correlation between non-denaturing isoelectric focusing and our system for pI assignment of light chains. This has importance due to reports of the potential importance of light-chain pI in the development of renal disease in patients with monoclonal gammopathies.

Reproducibility and quality assurance of two-dimensional gel electrophoresis of serum specimens.

Currently we are using two different ISO-DALT two-dimensional gel electrophoresis systems, designated MC-Iso 1 and MC-Iso 2, for the analysis of serum and plasma samples. Here we report quality-assurance data for both of these systems. CV values for the slopes of the pH gradient (ISO dimension) are 5.6% of less; CV values for the slopes of the molecular-mass curves (log Mr vs relative mobility in the DALT dimension) are 3.4% or less. We examined the various steps of the analysis in detail for reproducibility and protein loss, using radiolabeled albumin, alpha 2-macroglobulin, and beta 2-microglobulin. Generally, in the first dimension, less protein enters the MC-Iso 2 gels (our routine system in which silver stain is used) than enters the MC-Iso 1 gels (our wide-range system for myeloma serum samples, in which the gel is stained with Coomassie Blue), on the average, 87% as much. The CV at this stage for both systems is 5--8%. During equilibration, considerable amounts of protein are lost (approximately 30% in 10 min) from the ISO gel, and the reproducibility is also decreased. Resolution in the DALT dimension has, in most cases, little or no effect on either recovery or reproducibility. Overall, for most proteins expected to appear in an ISO gel of a given pH range, approximately 50--60% of the starting material may be expected to reside in the sodium dodecyl sulfate slab gel, under our conditions. The two most important variables affecting recovery are the concentration of the NaOH (used as catholyte) and the pH of the starting sample. The overall CV for the process is between 8 and 12%.

Patterns for normal colon mucosa and colon adenocarcinoma compared by two-dimensional gel electrophoresis.

A two-dimensional gel "map" of the proteins in normal cells and transformed cells may well help establish the presence of putative tumor-specific protein antigens, which can be isolated and used as antigens. We so examined normal colon mucosa and colon adenocarcinoma, using a sensitive silver stain. Samples were promptly prepared after excision by rapidly trimming the tissue to a small, grossly homogeneous piece, which was frozen on solid CO2. Frozen histological sections and permanent mounts were also prepared for several areas, to document the cellular constitution and to grade the carcinoma. Sample preparation for electrophoresis is described. The DNA was pelleted by centrifugation (108 000 x g x 1.5 h). Little or no pellet was observed, indicating complete solubilization. Many of the tumors contained proteases, liberated during sample preparation, so protease inhibitors were included. A highly reproducible pattern was observed for normal mucosa. Comparison of the gels from paired samples with histological data allows many of the spots to be tentatively assigned to the different cell types present in the mucosa (epithelium, connective tissue, or muscularis mucosa) and, in most tumors analyzed, detection of a series of spots that are not detectable in the pattern for normal tissue. These apparently tumor-associated proteins may be of epithelial cell or stromal origin.

Two-dimensional gel electrophoresis of serum specimens from a normal population.

We examined sera from a normal population by two-dimensional gel electrophoresis, to establish the normal pattern of serum proteins and to investigate genetic polymorphisms. With such information in hand, specimens from patients with certain diseases may be readily evaluated. Towards this goal, we optimized the ISO-DALT system (Proc. Natl, Acad, Sci, USA 74: 5421--5425, 1977) for routine phenotyping of alpha 1-antitrypsin, haptoglobin, GC-globulin, alpha 2-HS-glycoprotein, and transferrin, as well as a previously unknown polymorphic protein. We examined the effects of aging the specimens for 2 h at room temperature (no changes) or at -20 degrees C for several months (small changes), as well as serum/plasma differences and the effect of protease inhibitors. Silver-stain methods were modified to allow simultaneous staining of 10 gels, with reasonably good reproducibility of stain intensity. We quantitated silver-stained gels by densitometry of photographic transparencies. Very small samples suffice with this stain (0.5 microL of serum or plasma), allowing the use of "finger-stick" methods instead of venipuncture, yet the patterns are better resolved and easier to read than those for 10-microL specimens processed on gels stained with Coomassie Blue. Our techniques for rapidly removing albumin and IgG allow the investigator to examine areas on the gel that ordinarily are obscured. The region of haptoglobin has been examined by using serum from an ahaptoglobinemic donor. Finally, we present an expanded "normal" map illustrating the composite protein pattern.