SEARCH · PubMed Health

Results for “Restrictive”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources

PubMed1993

Effects of amino acid restriction during starter and grower periods on subsequent performance and incidence of leg disorders in male large white turkeys.

Male Nicholas Large White turkeys were fed diets formulated to meet a minimum of 100, 110, or 120% of NRC (1984) amino acid recommendations. There were three periods when 75% of recommended standards were fed: 0 to 3 wk, 0 to 6 wk, or 6 to 12 wk. A fourth (control) group was not restricted at any time. Four pens of 12 males were fed each amino acid by restriction combination. At 18 wk, leg scores were assigned to all birds and representative samples of birds processed for parts yield. All birds fed restricted diets had significantly lower BW at 18 wk than unrestricted controls but did not differ in feed utilization. Dietary amino acid levels significantly influenced BW and feed utilization, but there was no interaction with restriction times. There were no significant effects of amino acid levels or restriction times on incidence of leg disorders. Breast meat yields (quantity and percentage of carcass) were significantly influenced by both restriction time and amino acid levels. There seemed to be little if any compensatory gain following amino acid restriction in these studies.

Amino Acids↗

PubMed1995

Effects of feed restriction on growth and reproduction in randombred and selected lines of Japanese quail.

Feed restriction (70% of ad libitum consumption) was carried out from 1 d after hatching until 44 d in a randombred quail line and until 28 d in a quail line selected for high 4-wk BW. Body weights of restricted quail were significantly lower than ad libitum controls during restriction. Two weeks after restriction ended, however, BW were no longer different. Mortalities were twice as high under restriction. Hatchability of eggs was not affected by restriction, but restricted quail of the selected line laid fewer double-yolk eggs than ad libitum controls.

Age Factors↗

PubMed1995

Effect of full feed and early feed restriction on broiler performance, abdominal fat level, cellularity, and fat metabolism in broiler chickens.

Three hundred sixty Peterson x Arbor Acres chicks were fed two feed regimens to compare their effects on adipose cellularity, adipocyte lipolysis, hepatic glucose oxidation, adipocyte lipogenesis, bird performance, and abdominal fat level. Broilers in the first regimen had ad libitum access to feed throughout the 7-wk experiment, whereas broilers in the second regimen consumed feed at will throughout the experiment except that they were subjected to feed restriction (1.49 kcal/g BW2/3 daily) from 7 to 12 d of age (DOA). No differences in mean body weights were observed between the full-fed and restricted males and combined sex broilers at 49 DOA. Feed conversion and abdominal fat levels of female and combined sex were lower (P < .05) for the restricted than full-fed broilers. No differences in adipocyte numbers based either on whole abdominal fat pads at 28 and 42 DOA or per gram fat at 42 DOA were observed between broilers fed the two feed regimens. However, the adipocyte numbers per gram fat at 28 DOA were greater (P < .05) for the restricted broiler than for the broilers that ate freely. Lipolysis based per million adipocytes was not different between the treatments at 28 and 42 DOA; however, lipolysis based on per gram adipose tissue was increased (P < .05) with the addition of isoproterenol and theophylline for the restricted broilers compared to the full-fed broilers at 28 DOA. No difference was observed between the feed regimens at 42 DOA with hormone addition. Lipogenesis of the restricted broilers was lower (P < .05) than that of the full-fed broilers at 14 and 56 DOA. No difference in glucose oxidation was found between chickens fed the two regimens. Reduced abdominal fat in the restricted broilers is attributed to the reduction of adipocyte volume, which may be due to decreased lipogenesis.

Adipocytes↗

PubMed2000

Identification of major epitopes of Mycobacterium tuberculosis AG85B that are recognized by HLA-A*0201-restricted CD8+ T cells in HLA-transgenic mice and humans.

CD8(+) T cells are thought to play an important role in protective immunity to tuberculosis. Although several nonprotein ligands have been identified for CD1-restricted CD8(+) CTLs, epitopes for classical MHC class I-restricted CD8(+) T cells, which most likely represent a majority among CD8(+) T cells, have remained ill defined. HLA-A*0201 is one of the most prevalent class I alleles, with a frequency of over 30% in most populations. HLA-A2/K(b) transgenic mice were shown to provide a powerful model for studying induction of HLA-A*0201-restricted immune responses in vivo. The Ag85 complex, a major component of secreted Mycobacterium tuberculosis proteins, induces strong CD4(+) T cell responses in M. tuberculosis-infected individuals, and protection against tuberculosis in Ag85-DNA-immunized animals. In this study, we demonstrate the presence of HLA class I-restricted, CD8(+) T cells against Ag85B of M. tuberculosis in HLA-A2/K(b) transgenic mice and HLA-A*0201(+) humans. Moreover, two immunodominant Ag85 peptide epitopes for HLA-A*0201-restricted, M. tuberculosis-reactive CD8(+) CTLs were identified. These CD8(+) T cells produced IFN-gamma and TNF-alpha and recognized Ag-pulsed or bacillus Calmette-Guérin-infected, HLA-A*0201-positive, but not HLA-A*0201-negative or uninfected human macrophages. This CTL-mediated killing was blocked by anti-CD8 or anti-HLA class I mAb. Using fluorescent peptide/HLA-A*0201 tetramers, Ag85-specific CD8(+) T cells could be visualized in bacillus Calmette-Guérin-responsive, HLA-A*0201(+) individuals. Collectively, our results demonstrate the presence of HLA class I-restricted CD8(+) CTL against a major Ag of M. tuberculosis and identify Ag85B epitopes that are strongly recognized by HLA-A*0201-restricted CD8(+) T cells in humans and mice. These epitopes thus represent potential subunit components for the design of vaccines against tuberculosis.

Acyltransferases↗

PubMed2000

MHC class Ib-restricted CTL provide protection against primary and secondary Listeria monocytogenes infection.

Infection of B6 mice with the intracellular pathogen Listeria monocytogenes (LM) results in the activation of CD8(+) T cells that respond to Ag presented by both MHC class Ia and class Ib molecules. Enzyme-linked immunospot analysis reveals that these CTL populations expand and contract at different times following a primary sublethal LM infection. Between days 4 and 6 postinfection, class Ib-restricted CTL exhibit a rapid proliferative response that is primarily H2-M3 restricted. The peak response of class Ia-restricted CD8(+) T cells occurs a few days later, after the majority of bacteria have been cleared. Although class Ia-restricted CTL exhibit a vigorous recall response to secondary LM infection, we observe limited expansion of class Ib-restricted memory CTL, even in MHC class Ia-deficient mice (B6.K(b-/-)D(b-/-)). Despite this lack of enhanced expansion in vivo, class Ib-restricted memory CTL retain the ability to proliferate and expand when provided with Ag in vitro. Furthermore, we demonstrate that in vivo depletion of CD8(+) T cells in LM-immune B6.K(b-/-)D(b-/-) mice severely impairs memory protection. Together, these data demonstrate that class Ib-restricted CTL play an important role in clearing a primary LM infection and generate a memory population capable of providing significant protection against subsequent infection.

Animals↗

PubMedDate not supplied

The impact of organizational characteristics on smoking policy restrictions in midwestern hospitals.

Purpose. The relationship between hospitals' organizational characteristics and adoption of restrictive smoking policies was examined. Design. Self-administered questionnaires and telephone interviews were conducted prior to and following the target date for policy implementation. Setting. The Director of Regional Medical Services of a community network of hospitals requested in the summer of 1989 that the 57 member hospitals voluntarily implement a policy prohibiting all smoking in hospital buildings as of January 1, 1990. Subjects. Subjects were the 49 hospital CEOs (86%) who provided data at both time points. Intervention. The Director of Regional Medical Services made a personal request of the CEO during a routine visit at each hospital. Measures. Measures included structural aspects of the hospitals (e.g., number of employees, number of beds, presence of chemical dependency and psychiatric units); orientation toward employee health; support for smoking restrictions among various groups; and extent of CEO authority to set smoking policy. Results. Fifty-one percent of hospitals increased the restrictiveness of their smoking policy; 35% adopted a complete indoor smoking ban. Stepwise multiple regression analysis demonstrated that adoption of additional smoking restrictions was related to CEOs' and perceived board of directors' support of smoking restrictions, absence of a chemical dependency unit, and experience of financial difficulties in the previous two years. Conclusions. It is important to educate top decision makers as to the necessity of restrictive smoking policies. Barriers to smoking restrictions in organizations with chemical dependency units deserve particular attention from health promotion practitioners and researchers.

Hospital Administration↗

PubMed2003

Umbilical cord morphologic characteristics and umbilical artery Doppler parameters in intrauterine growth-restricted fetuses.

OBJECTIVE: To compare prenatal morphometric changes of umbilical cord components in intrauterine growth-restricted fetuses with and without abnormal umbilical artery Doppler parameters. METHODS: Consecutive singleton intrauterine growth-restricted fetuses at a gestational age of older than 20 weeks were compared with matched appropriate-for-gestational-age fetuses. Intrauterine growth restriction was defined in the presence of a sonographic abdominal circumference below the 5th percentile for gestational age at the time of sonography and a birth weight below the 10th percentile. The sonographic examination included pulsed Doppler measurements of the umbilical artery resistance index and measurements of the umbilical cord cross-sectional area and the umbilical cord vessel area. RESULTS: A total of 84 intrauterine growth-restricted fetuses and 168 appropriate-for-gestational-age fetuses were included in the study. All umbilical cord components (umbilical cord cross-sectional area, vein area, artery area, and Wharton jelly area) were smaller in the intrauterine growth-restricted fetuses. The prevalence of lean umbilical cords (cross-sectional area < 10th percentile for gestational age) was significantly higher in intrauterine growth-restricted fetuses compared with appropriate-for-gestational-age fetuses (73.8% versus 11.3%; P < .0001). A significant and progressive reduction of the umbilical vein area corresponding to the degree of umbilical artery Doppler parameter abnormality was found. The umbilical artery area was not related to the hemodynamic changes of the blood flow in the umbilical arteries. CONCLUSIONS: The proportion of lean umbilical cords was higher in intrauterine growth-restricted fetuses than in appropriate-for-gestational-age fetuses. Umbilical vein caliber decreases significantly with worsening of umbilical artery Doppler parameters.

Adult↗

PubMed1998

The effect of age and dietary restriction on bone strength, calcium and phosphorus contents of male F344 rats.

At 6 weeks of age, male Fischer F344 rats were fed a purified, casein based diet either ad libitum or in the amount of 60% of the diet consumed by the rats, fed ad libitum (restricted diet). Femur bone tissues were obtained from the rats at 4 and 13 months of age. The femurs of the animals fed ad libitum were significantly stronger than the femurs of the animals fed a restricted diet both at the age of 4 and 13 months [p0.01]. The body weight and bone weight of the animals fed ad libitum were also higher than that of the animals on the restricted diet. The bone ash weight was significantly lower for food restricted animals [p0.013] when compared to the animals fed ad libitum. The bone phosphorus content was significantly higher in the diet restricted older animals [p0.02] when compared to the diet restricted younger animals. Results indicate that food restriction will delay bone maturation.

Age Factors↗

PubMedDate not supplied

Placental expression of insulin-like growth factor receptor-1 and insulin receptor in the growth-restricted fetal rat.

OBJECTIVE: The type 1 insulin-like growth factor receptor (IGF-R1), which resembles the insulin receptor (INS-R), is expressed abundantly in the placenta. The regulation of fetal growth by IGFs and insulin might reflect their actions on the placenta. This study compared the placental expression of IGF-R1 and INS-R in growth-restricted and normal pregnancies. METHODS: Fetal growth restriction was produced in Sprague-Dawley rats by bilateral ligation of the uterine artery on day 19 (term = 21.5 days). Fetuses were delivered by hysterotomy on day 20, and placental samples were frozen. Fetuses that had been subjected to a sham operation of maternal laparotomy without uterine artery manipulation were studied as matched controls. IGF-R1 and INS-R message was assessed by reverse transcription and polymerase chain reaction amplification of extracted placental RNA. The receptors also were assessed by Western blotting of extracted placental protein. Measurements for the growth-restricted group were expressed as a multiple of that of the matched sham litter. RESULTS: Placental IGF-R1 messenger RNA (mRNA) level was significantly lower in the growth-restricted fetuses (0.66 x sham [0.47-0.93], P <.05), but INS-R mRNA was not different (0.89 x sham [0.63-1.3], P >.5). IGF-R1 protein transcript was similarly reduced in the growth-restricted fetuses (0.78 x sham [0.69-0.88], P <.005), but the INS-R protein transcript was not (0.98 x sham [0.69-1.4], P >.8). Birth weights were significantly less in the growth-restricted group (3.06 +/- 0.07 versus 3.29 +/- 0.06 g, P =.016); placental weights were not (0.54 +/- 0.02 versus 0.54 +/- 0.02 g, P =.90). CONCLUSIONS: The placenta responds to decreased nutrient delivery with decreased expression of IGF-R1. This would reduce the growth-promoting effects of insulin-like growth factors, which include augmentation of placental lactogen production and glucose and amino acid transport. INS-R was unaffected, which suggests that placental response to insulin is less important than its response to insulin-like growth factors in growth restriction.

Animals↗

PubMed1992

Aging and proliferative homeostasis: modulation by food restriction in rodents.

In rats fed ad libitum, the fat cell number increases with advancing age; the temporal pattern of this increase differs in the perirenal depot compared with the epididymal depot. Restriction of energy intake reduces the number of fat cells in fat depots whether the restriction is started soon after weaning or in adult life. The capacity for diet to modulate fat cell number is maintained through most, if not all, of the life span. Restriction of energy intake delayed death due to neoplasms; restriction of dietary fat or protein without restriction of energy did not have this action. In the case of leukemia/lymphoma, the data indicated that it was the age of occurrence that was delayed by the restriction of energy intake. Because restriction of dietary energy maintains most physiologic systems in a youthful state and retards a broad spectrum of disease processes, the importance of its effects on cellularity and cell proliferation in its anti-aging action remains to be established.

Adipose Tissue↗

PubMed1992

Protein restriction affects fat intake and serum lipids in children with chronic renal failure.

Cardiovascular complications in patients with chronic renal failure have been associated with the hyperlipidemia present in many of these patients. Since a protein-restricted diet is often prescribed in an attempt to preserve renal function, we performed a randomized controlled study in children with chronic renal failure on the effect of a protein-restricted diet on fat intake and serum lipid profiles. Although total fat intake did not change, we found a lower cholesterol intake and a higher polyunsaturated/saturated fat ratio in the patients with the protein-restricted diet. This is probably caused by the restriction of animal protein which results in the replacement of animal fat by vegetable fat in the protein-restricted group. Moreover, we observed an increase of plasma cholesterol and low-density lipoprotein cholesterol in patients with a normal protein intake which was absent in the protein-restricted group. This suggests a favourable effect of the institution of a protein-restricted diet on lipid intake and plasma profile.

Adolescent↗

PubMed1992

Tibia development in turkeys and chickens as affected by early-age feed restriction.

Tibia development was studied by histomorphometry in male chickens and turkeys fed ad libitum throughout the growing period, or subjected to an early-age (1-week) severe feed restriction for 6 and 14 days, respectively. In turkeys, the rates of longitudinal bone growth and epiphyseal width growth, both dependent on the activity of chondrocytes, proceeded rapidly and reached maxima at early ages of 24 and 11 days, respectively. Moreover, longitudinal bone growth and the growth of epiphyseal width were reduced during early-age feed restriction, in both chickens and turkeys. On the other hand, the rate of growth of metaphyseal width, determined by activity of bone cells such as osteoclasts and osteoblasts, reached in turkeys a maximum at the relatively late age of 70 days, and was not influenced by feed restriction. Rhythmic variation characterized the temporal behavior of the height of the hypertrophic and non-hypertrophic zones of the growth plate, the trabecular width, and the osteoclasts number at the subchondral region. Rhythmicity appeared similar in both ad libitum-fed and early-age feed-restricted birds of both species. The height of the non-hypertrophic epiphyseal cartilage appeared not to change, whereas the hypertrophic zone decreased with age and early-age feed restriction, demonstrating the importance of cartilage cell hypertrophy as a main determinant of longitudinal bone growth. Sexual maturation was accompanied by the disappearance of both hypertrophic and non-hypertrophic zones of the epiphyseal growth plate and the end of bone elongation. Trabecular width at the end of bone elongation. Trabecular width at the subchondral region increased while osteoclast number decreased with age, reflecting the net increase in bone mass, but were not affected significantly by early age feed restriction. Compensatory growth of the early-age feed-restricted birds, resulted in the complete recovery of affected bone variables within a few weeks of resumed ad libitum feed intake.

Aging↗

PubMed2004

Modulating the homeostatic process to predict performance during chronic sleep restriction.

BACKGROUND: In most current sleep/performance models, the homeostatic process is generally conceived as a simple reservoir in which performance capacity increases exponentially during sleep and decays either linearly or exponentially during wakefulness. Models that include this notional homeostatic process have been successful for describing sleep-performance data under conditions of irregular sleep schedules, jet lag, and short periods of total sleep loss. However, recently described data from sleep restriction studies indicate that recovery following chronically restricted sleep is considerably slower than would be predicted by these models. These findings suggest that chronic sleep restriction induces relatively long-term, slow-recovering changes in brain physiology that affect alertness and performance. METHODS: This paper describes, both conceptually and mathematically, a generic modification to sleep/performance models that facilitates the ability to predict the rate at which alertness and performance restoration occurs during recovery sleep following chronic sleep restriction. Weighted nonlinear least-squares methods were used to compare the proposed modulated homeostatic model with recent sleep/performance observations during chronic sleep restriction and recovery. RESULTS: When compared with the classical Walter Reed homeostatic model, this proposed model was found to provide a better description of sleep restriction and recovery observations. The proposed model was also found to be consistent with the data from a recent University of Pennsylvania study. CONCLUSIONS: These two models make significantly different predictions of performance during both the recovery phase and the chronic sleep restriction phase.

Data Interpretation, Statistical↗

PubMed2005

Risk factors for prevalence of and mortality related to restriction on spirometry: findings from the First National Health and Nutrition Examination Survey and follow-up.

OBJECTIVE: To define risk factors for both restriction on spirometry and subsequent mortality in a national cohort of US adults. METHODS: Participants in the First National Health and Nutrition Examination Survey (NHANES I) were followed for up to 22 years. Subjects were classified using the forced expiratory volume in one second (FEV1), the forced vital capacity (FVC), and the FEV1/FVC ratio into subgroups with and without restriction on spirometry. Regression models were developed to determine risk factors for restriction on spirometry and death. RESULTS: Our final cohort consisted of 4320 subjects, of whom 481 (10.3 weighted %) had restriction on spirometry. The largest risk factors for restriction on spirometry were a cardiothoracic ratio of >55% (OR 4.3, 95%CI 3.1-5.9), race other than black or white (OR 3.7, 95%CI 1.8-7.8), and a history of stroke or paralysis (OR 1.8, 95%CI 1.1-2.9). The overall mortality rate was increased in subjects with restriction on spirometry (25.7 vs. 10.3 deaths per 1000 person-years). CONCLUSIONS: Restriction on spirometry is associated with comorbid disease and increased mortality, and is present in a significant proportion of the population.

Adult↗

PubMed2005

Nutrition knowledge, attitudes and dietary restriction behaviour of Taiwanese elderly.

The purpose of this study is to understand knowledge about and general attitudes towards nutrition, dietary restriction attitudes, and dietary restriction behavior in the Taiwanese elderly, and the relationship of these various components to each other. Data from the Elderly Nutrition and Health Survey in Taiwan (1999-2000) were used for analysis and included 1937 elderly persons aged over 65. The results indicated that the elderly had poor nutrition knowledge, especially about the relationship between nutrition and disease. Elderly nutrition attitudes were fair; they tended to disagree with misconceptions about "healthy" or functional foods and also had quite positive general eating attitudes. However, the Taiwanese elderly hold quite strong attitudes influenced by Chinese traditional or food-texture-related dietary restrictions. Elderly people frequently avoid eating foods considered unhealthy by modern medical science (e.g. high fat/cholesterol foods) as well as foods forbidden by Chinese traditional medicine (e.g. "heating" foods, "cooling" foods). Most of the elderly regularly eat three meals a day, however, they seldom pay attention to dietary and nutrition information. The most important sources of nutrition information are offspring or family members, TV, and medical practitioners. In general, elderly men with a higher educational level and living in less remote areas had better nutrition knowledge, held more positive nutrition attitudes, and kept to dietary restrictions less frequently. Elderly people's nutrition knowledge was positively related to their health-care attitudes, general eating attitudes, high- fat or high-cholesterol food restriction behavior, fermented or pickled food restriction behavior, attention to nutrition information, and regularity of meals. However, nutrition knowledge was inversely related to Chinese traditional or food-texture-related dietary restriction behaviors. The results of this study suggest that education of elderly people about nutrition is important, and the design of such nutrition education programs should consider the low educational levels of the elderly. Children or other family members may also be included in the program. The use of TV as a medium for nutrition education of the elderly may also be important for nutrition educators.

Aged↗

PubMed2005

Risk factors for participation restriction in leprosy and development of a screening tool to identify individuals at risk.

The World Health Organisation International Classification of Functioning, Disability and Health defines participation as involvement in a life situation. Participation restrictions are problems experienced in any life situation, for example, in relationships or in employment. Our research explored risk factors for participation restrictions experienced by people affected by leprosy. Our objective was to develop a screening tool to identify individuals at risk. An initial round of qualitative fieldwork in eight centres in Nepal, India and Brazil identified 35 potential risk factors for participation restriction. These were then further assessed through quantitative fieldwork in six centres in India and Brazil. In all, 264 individuals receiving leprosy treatment or rehabilitation services made a retrospective assessment of their status at time of diagnosis. Their level of participation restriction was assessed using the Participation Scale. Regression analysis identified risk factors for participation restriction including fear of abandonment by family members (odds ratio 2.63, 95% CI 1.35-5.13) and hospitalization at diagnosis (3.98, 1.0-7.32). We recommend four consolidated items as the basis for a simple screening tool to identify individuals at risk. These are the physical impact of leprosy, an emotional response to the diagnosis, female gender and having little or no education. Such a tool may form the basis for a screening and referral procedure to identify newly diagnosed individuals at risk of participation restrictions and in need of actions that may prevent such restrictions.

Adolescent↗

PubMed1991

Dietary restriction permits normal parturition and lactation but suppresses mouse mammary tumor virus proviral transcription even after mammary involution.

Dietary restriction of C3H/Ou mice prevents development of spontaneous mammary adenocarcinoma by suppressing mammary expression of the mouse mammary tumor virus (MMTV) via a mechanism which may involve prolactin. In the present study, dietary restriction of 40% was imposed for 16 weeks on nulliparous C3H/Ou mice, interrupted by ad libitum consumption at mating and continued only during pregnancy and lactation, with 40% energy restriction reimposed at the end of lactation. The results show that mammary MMTV mRNA expression levels of chronic energy intake restricted (CEIR) mice and ad libitum fed mice are similar and elevated during early lactation, when all mice of both groups are being fed ad libitum energy levels. In spite of this, and in marked contrast, when CEIR dams are returned to 40% dietary restriction following the weaning of litters, mammary MMTV transcription is suppressed to levels 4-5-fold less than those measured in mammary glands from ad libitum fed controls. Within the 38 weeks of study, 73% of ad libitum fed uniparous mice at risk and 11% of CEIR uniparous mice at risk developed mammary tumors, yet mice of both dietary groups delivered and weaned healthy litters with comparable efficiency. When dietary restriction is maintained in CEIR mice during pregnancy and lactation, efficiency of conception and litter size are reduced, and MMTV transcription is suppressed even during lactation. Mean serum prolactin levels were not significantly different among dietary groups. These findings show that the level of MMTV transcription is rigorously influenced by dietary energy level, and that 40% dietary restriction of C3H/Ou mice not only suppresses mammary MMTV transcription and prevents mammary tumor development in uniparous mice, but also permits normal conception, gestation, lactation, and the production of healthy litters as long as the nutritional demands of gestation and lactation are met.

Adenocarcinoma↗

PubMed1992

The class II MHC-restricted presentation of endogenously synthesized ovalbumin displays clonal variation, requires endosomal/lysosomal processing, and is up-regulated by heat shock.

LB27.4 cells (a B lymphoblastoid APC) were transfected with a plasmid containing an OVA cDNA. Functional analysis of six independent clones yielded three patterns of MHC-restricted presentation of the endogenously synthesized OVA. A clone displayed either: 1) strong class I and class II-restricted presentation, 2) strong class I but little or no class II-restricted presentation or, 3) only a modest class I-restricted presentation. There was no clonal variation in class II-restricted presentation of exogenous Ag or in the amount of surface class I or II molecules. Heat shock increased the presentation of endogenous but not exogenous Ag with class II. These results indicate that an endogenously synthesized Ag both constitutively and during heat shock can gain access to the class II, MHC-restricted, presentation pathway. The amount of OVA synthesized by a cell correlated with whether OVA-class II complexes were detected. However, the amount of OVA secreted into the extracellular fluid was not sufficient to sensitize APC, which suggests that endogenously synthesized OVA enters the class II pathway of Ag presentation by an intracellular route rather than by an extracellular/reuptake route. Also, the functional and quantitative analysis of the clones suggests that endogenously synthesized OVA was presented more efficiently with class I as compared to class II-MHC molecules. Leupeptin and chloroquine inhibited the class II-restricted presentation of endogenously synthesized OVA. Together these results indicate that endogenously synthesized OVA can gain access to an endosomal/lysosomal compartment via an intracellular route and be processed and presented in association with class II-MHC molecules.

Animals↗