The augmentation of tumor-specific immunity using haptenic muramyl dipeptide (MDP) derivatives

Summary A new haptenic compound, a muramyl dipeptide (MDP) derivative (designated as L4-MDP-ONB) cross-reactive with Bacillus Calmette Guerin (BCG) was synthesized. The cross-reactivity of L4-MDP hapten to BCG was demonstrated from the following evidence; (a) lymph node cells from BCG-primed C3H/HeN mice exhibited appreciable L4-MDP-specific proliferative responses to the in vitro stimulation of L4-MDP-modified syngeneic cells (L4-MDP-self); (b) inoculation of L4-MDP-self into footpads of BCG-primed C3H/HeN mice elicited ample delayed type-hypersensitivity (DTH) responses in vivo as measured by footpad swelling; and (c) BCG-primed mice contained L4-MDP-reactive helper T cell activity which functions to augment the generation of effector T cell responses to cell surface antigens. This crossreactivity between L4-MDP hapten and BCG as measured by the helper T cell activity was applied to enhanced induction of tumor-specific immunity. When BCG-primed C3H/HeN mice were immunized with L4-MDP-modified syngeneic X5563 tumor cells, these mice could generate augmented tumor-specific in vivo protective (tumor neutralizing) immunity as well as in vitro cytotoxic T cell responses. These results indicate the effectiveness of L4-MDP hapten in augmenting tumor-specific immunity. The present approach is discussed in the context of potential advantages of this new hapten for its future application to clinical tumor systems.     

NESTMATE RECOGNITION AND KIN RECOGNITION IN ANTS

Abstract  All ants (Hymenoptera, Formicidae) are highly eusocial insects that are characterized by reproductive division of labor with sterile castes (worker and soldier) helping fertile castes (queen and male) to reproduce.
Ant societies, like other complex animal societies, have developed a sophisticated communication system, in which recognition behaviors are frequently involved Recognition abilities allow individuals to orient and modulate their behaviors effectively and appropriately in response to the characteristics andlor signals expressed by other organisms. Among recognition behaviors, nestmate recognition and kin recognition mechanisms have attracted great attention of sociobiologists, ecologists, insect physiologists and biochemists since 1970's. This is parallel with the popularization of Hamilton's kin selection theory. The present paper aims at reviewing the current understanding on nestmate/kin recognition in ants. This review consists of three parts. The first part concerns the diversity of recognition behaviors and their ecological implications with emphasis on nestmatelkin recognition; in the second part, the current understandings on the mechanism of nestmatelkin recognition are outlined; and in the third part, we discuss the ontogenetic development of nestmate recognition behavior and naturally mixed colonies. The study of the integration mechanism of social parasite may provide heuristic clues to the understanding of kin/nestmate recognition system.     

Study of insulin response to oral glucose load after acute and chronic glycemic control in type 2 diabetic subjects

To investigate whether correction of fasting hyperglycemia per se improves the insulin secretion in type 2 diabetic subjects, plasma insulin response to 75 g oral glucose load has been studied after acute and chronic normalization of fasting plasma glucose levels in 7 overt type 2 diabetic subjects. For the acute normalization of elevated fasting plasma glucose levels, an artificial endocrine pancreas was employed. Although fasting plasma glucose concentrations were normalized before the oral glucose challenge, insulin response to oral glucose was not improved compared to those without normalization of fasting plasma glucose levels. After 1-3 month control of hyperglycemia, the insulin response to glucose in the subjects was significantly improved compared to those without treatments. Results indicate that chronic metabolic control is essential for the improvement of insulin response to glucose in type 2 diabetic subjects, and also suggest that the impaired insulin secretion in type 2 diabetes is not due to hyperglycemia per se, but due to the metabolic derangements which lead to chronic hyperglycemia.     

Hydrolysis of beef tallow by lipase from Pseudomonas sp

The lipase produced by Pseudomonas fluorescens biotype I was selected for hydrolyzing beef tallow at 50-70 degrees C to more than 90% of reaction ratio. Using an amount of lipase sufficient to reach equilibrium, the final reaction ratio was decreased with increasing temperature and the apparent enthalpy of beef tallow hydrolysis obtained by the final reaction ratio was -1.93 x 10(4)cal/mol, and the final reaction ratio also decreased with increasing substrate concentration. The rising time, which is the reaction time up to one-half of the final reaction ratio, decreased remarkably with increasing temperature, and was closely related to the value of the maximum velocity by the Michaelis constant of this lipase. The final reaction ratio increased with increasing lipase amount up to equilibrium. Increasing the lipase above the amount required to reach equilibrium caused a decrease in the rising time. The feasibility of using parameters obtained by a hyperbolic simulation of the progress curve is discussed.     

Quantitative estimation of the pathways followed in the conversion to glycogen of glucose administered to the fasted rat

When [6-3H,6-14C]glucose was given in glucose loads to fasted rats, the average 3H/14C ratios in the glycogens deposited in their livers, relative to that in the glucoses administered, were 0.85 and 0.88. When [3-3H,3-14C]lactate was given in trace quantity along with unlabeled glucose loads, the average 3H/14C ratio in the glycogens deposited was 0.08. This indicates that a major fraction of the carbons of the glucose loads was converted to liver glycogen without first being converted to lactate. When [3-3H,6-14C]glucose was given in glucose loads, the 3H/14C ratios in the glycogens deposited averaged 0.44. This indicates that a significant amount of H bound to carbon 3, but not carbon 6, of glucose is removed within liver in the conversion of the carbons of the glucose to glycogen. This can occur in the pentose cycle and by cycling of glucose-6-P via triose phosphates: glucose----glucose-6-P----triose phosphates----glucose-6-P----glycogen. The contributions of these pathways were estimated by giving glucose loads labeled with [1-14C]glucose, [2-14C]glucose, [5-14C]glucose, and [6-14C]glucose and degrading the glucoses obtained by hydrolyzing the glycogens that deposited. Only a few per cent of the glucose carbons deposited in glycogen were deposited in liver via glucose-6-P conversion to triose phosphates. Between 4 and 9% of the glucose utilized by the liver was utilized in the pentose cycle. While these are relatively small percentages, since three NADP3H molecules are formed from each molecule of [3-3H]glucose-6-P utilized in the cycle, a major portion of the difference between the ratios obtained with [3-3H]glucose and with [6-3H]glucose is attributable to metabolism in the pentose cycle. Because 3H of [3-3H]glucose is extensively removed during the conversion of the glucose to glycogen within liver the extent of incorporation of the 3H into liver glycogen is not the measure of glucose's metabolism in other tissues before its carbons are deposited in liver glycogen. The distributions of 14C from the 14C-labeled glucoses into the carbons of the liver glycogens mean that at a minimum about 30% of the carbons of the glucose deposited in the glycogen were first converted to lactate or its metabolic equivalent.     

New human colorectal carcinoma cell lines that secrete proteinase inhibitors in vitro

Two new human cell lines, RCM-1 and CoCM-1, have been established from primary colorectal adenocarcinomas. Both cell lines were unique in that the cultures secreted trypsin inhibitors in vitro. The activities of these inhibitors were accumulated in serum-free media of both cell lines over a period of several days. Two inhibitors (PI-1 and PI-2) were isolated from serum-free conditioned medium in which RCM-1 was grown by anion-exchange and gel filtration high-performance liquid chromatography. PI-1 inhibited trypsin and chymotrypsin strongly, and pancreatic elastase weakly. Its molecular weight was about 57 kilodaltons (Kd) as determined by gel filtration chromatography. It cross-reacted with the antiserum elicited against human α₁-antitrypsin in double immunodiffusion. PI-1 corresponding to α₁ - antitrypsin was also demonstrated immunohistochemically in both cell lines. PI-2 inhibited trypsin strongly, and chymotrypsin, kallikrein and plasmin weakly. It had higher molecular weight (200–300 Kd) than that of PI-1, and did not crossreact with antisera against human α₁-antitrypsin, α₂-macroglobulin, α₁-antichymotrypsin, α₂-plasmin inhibitor, inter-α-trypsin inhibitor and urinary trypsin inhibitor. RCM-1 and CoCM-1 are the first colorectal adenocarcinoma cell lines that secrete functionally active trypsin inhibitors, including α₁-antitrypsin in vitro, and are useful for the study of tumor-cell derived proteinase inhibitors.     

Effect of cyclosporin A on lymphopoiesis. II. Developmental defects of immature and mature thymocytes in fetal thymus organ cultures treated with cyclosporin A

The effect of cyclosporin A (CsA) on early T cell development was studied by two-color flow cytometric and biochemical analyses using the fetal thymus organ culture system. Addition of CsA to organ culture resulted in a decreased cell yield and complete inhibition of the appearance of TCR-alpha beta-bearing, single positive thymocytes (both CD4+CD8- and CD4-CD8+). Furthermore, the generation of CD4+CD8+ thymocytes was markedly inhibited by CsA treatment, whereas the development of CD3-, CD4-CD8+ thymocytes and TCR-gamma delta-bearing, CD4-CD8- thymocytes was not affected. These results suggest that CsA induces a maturational arrest of T cells entirely within the thymic environment, and indicate that CsA-induced inhibition occurs at more than one stage of intrathymic T cell development.     

Interpretation of the thiobarbituric acid reactivity of rat liver and brain homogenates in the presence of ferric ion and ethylenediaminetetraacetic acid.

The thiobarbituric acid (TBA) reactivity of rat liver and brain homogenates was characterized to elucidate what kinds of aldehyde species contributed to the reactivity. Characteristic pH dependence of the reactivity with a maximum at around pH 3 and marked enhancement of the reactivity by t-butyl hydroperoxide (t-BuOOH) and ferric ion were similar to those of alkadienals. The amounts of aldehyde species, including alkadienals determined as 2,4-dinitrophenylhydrazones, were high enough to account for the enhanced reactivity. The reactivity was inhibited by ethylenediaminetetraacetic acid (EDTA) but not completely, suggesting the presence of malonaldehyde whose reactivity was not affected by EDTA. The amounts of malonaldehyde determined as 1-(2,4-dinitrophenyl)pyrazole could account for a part of the reactivity in the presence of EDTA. Hence, the TBA reactivity of liver and brain homogenates at around pH 3 in the presence of t-BuOOH and ferric ion may be accounted for by alkadienals and malonaldehyde and that in the presence of EDTA by malonaldehyde.