Detection of a serum class I molecule in rat with anti-rat liver beta-2-microglobulin

Rat serum was fractionated on a column of Sephacryl-300 and tested with a rabbit anti-rat beta-2-microglobulin (B2m) antiserum. This antiserum was directed against B2m purified from rat liver, and its specificity was confirmed by immunoprecipitation procedures. The antiserum recognized three peaks in the fractionated rat serum: a 200- to 300-kd (kilodalton) fraction, a 40- to 70-kd component, and the free 12-kd B2m. Indirect immunoprecipitation from the 200- to 300-kd fraction led to the identification of a 43-kd polypeptide associated with B2m. A xenoantiserum against RT1 class I antigen also precipitated a similar polypeptide from the same fraction, but this molecule differed in size and antigenic specificity from the one precipitated by anti-rat B2m.This work was supported in part by Grant 59010101 from the Ministry of Education, Science, and Culture, Japan.     

The effect of specific anti-rat thymocyte serum on cell-mediated tumor immunity and other lymphocyte functions

A burro anti-rat thymocyte serum (ATS) was rendered specific for thymus-derived lymphocytes (T cells) by repeated absorptions with Murphy-Sturm lymphoma cells. All of the cells in this lymphoma cell line were shown to have surface immunoglobulin and it was presumed to be bone marrow-derived. Treatment of lymphocytes with ATS eliminated stimulation by phytohemagglutinin and concanavalin A, but did not reduce the proportion of cells with surface immunoglobulin or complement receptor. ATS also did not decrease the number of antibody-producing spleen cells from rats immunized against sheep erythrocytes. The ATS was used to determine the nature of the effector cells in the cell-mediated cytotoxicity of immune W/Fu rat spleen cells against a syngeneic Gross virus-induced lymphoma. This cytotoxic response was consistently inhibited, indicating that T cells were needed for reactivity.     

Immunocytochemical localization of growth hormone releasing factor (GHRF)-containing structures in the rat brain using anti-rat GHRF serum

The distribution of growth hormone releasing factor (GHRF) immunoreactive structures in the rat hypothalmus was studied after colchicine treatment with PAP immunocytochemistry in vibratome sections using an antiserum directed to rat hypothalamic GHRF. The majority of the GHRF-immunoreactive cell bodies were found in the arcuate nucleus, the medial perifornical region, and the ventral premammillary nuclei of the hypothalamus. Scattered cells were seen in the lateral basal hypothalamus, the medial and lateral portions of the ventromedial nucleus, and the dorsomedial and paraventricular nuclei. Immunoreactive fibers were observed in all the regions mentioned above. GHRF terminals were located in the central region of the median eminence. In addition, GHRF-immunoreactive neuronal processes were seen in the ventral region of the dorsomedial nucleus, the medial preoptic and suprachiasmatic regions, dorsal portion of the suprachiasmatic nucleus, bed nucleus of the stria terminals and the hypothalamic portion of the stria terminals. The localization of GHRF-immunoreactive terminals in the median eminence reinforces the view that GHRF plays a physiological role in the regulation of pituitary function. In addition, the localization of GHRF-immunoreactive structures in areas not usually considered to project to the median eminence suggest that GHRF may act as a neuromodulator or neurotransmitter.     

Production of anti-rat islet cell surface antibody in guinea pigs

Anti-rat islet serum was prepared in guinea pigs by multiple subcutaneous inoculations of rat islets homogenates emulsified in complete Freund's adjuvant (CFA). The anti-rat islet serum was cytotoxic against rat spleen cells in the presence of complement and the nonspecific antibodies were observed with homogenates of rat livers and spleens. After absorption, the serum lost the cytotoxicity against the rat spleen cells yet showed specific cytotoxicity against the rat islet cells. The binding capacity of anti-rat islet antibody was determined by the indirect immunofluorescence test using FITC conjugated rabbit anti-guinea pig IgG serum. As the guinea pig anti-rat islet serum contained anti-insulin antibody, the role of this antibody in this cytotoxic activity and surface immunofluorescence was studied. However, the anti-insulin antibody used as the control showed neither cytotoxicity nor surface immunofluorescence. After neutralizing the anti-insulin antibody in the antiserum with insulin, the serum remained cytotoxic to the rat islet cells and a surface immunofluorescence appeared. These data show that specific anti-rat islet cell surface antibody can be produced in guinea pigs by multiple inoculations of rat islets homogenates with CFA.     

Assessing liver fibrosis with serum marker models

Chronic liver disease is characterised by liver fibrosis, which may lead to cirrhosis. Conventional serum-based liver function tests do not give information on either the presence or the rate of progress of liver fibrosis. The reference diagnostic test to detect fibrosis is liver biopsy, a procedure subject to various limitations, including risk of patient injury and sampling error.Serum markers have been evaluated for the determination of fibrosis either singly or combined as a panel of markers, however diagnostic accuracy is greatest in studies using a panel together with an algorithm, which generates a predictive score. Serum marker models, especially those targeted at hepatitis C, have multiplied in spectacular fashion over the last five years, with most models regularly achieving a median area under the receiver operating characteristic curve (ROCC) of 0.80 versus liver biopsy. Five years after publication of the first major serum marker model, the first study to document clinical outcomes reported that applying the model to hepatitis C patients improved prediction of decompensated cirrhosis and survival compared to liver biopsy.An obstacle to widespread adoption of serum marker models has been the lack of uniform performance indicators, such as diagnostic odds ratios and likelihood ratios. At present, serum marker models are not considered sufficiently reliable to replace liver biopsy in patients with chronic liver disease. However with continued evaluation in parallel with liver biopsy rapid advances are being made.     

Isolation of serum albumin-synthesizing polysomes from rat liver

The procedures for the purification of rat liver polysomes synthesizing serum albumin was developed, employing the quantitative precipitin method with rat serum albumin as a carrier and its antibody, and ribonuclease inhibitor from rat liver. The addition of ribonuclease inhibitor to polysomes during the incubation with antibody was found to prevent their degradation. Under these conditions, about 12 % of the membrane-bound polysomes of rat liver was found in the specific precipitate of serum albumin and its antibody, while a negligible amount of free polysomes was precipitated. It is concluded that polysomes synthesizing serum albumin are isolated by this method.