Does the Addition of a Gastroepiploic Artery to Bilateral Internal Thoracic Artery Improve Survival?

It is unclear whether the additional conduit to supplement bilateral internal thoracic arteries (BITA) influences the patient outcome in coronary surgery. This retrospective study compared long-term survival of patients undergoing left-sided BITA grafting in which the third conduit to the right coronary system (RCA) was either vein graft (SVG) or gastroepiploic artery (GEA). From 1989 to 2014, 1432 consecutive patients underwent left-sided revascularization with BITA associated with SVG (n = 599) or GEA (n = 833) to RCA. Propensity score was calculated by logistic regression model and patients were matched 1 to 1 leading to 2 groups of 320 matched patients. The primary end point was the overall mortality from any cause. GEA was used in significantly lower risk patients. The 30-day mortality was 1.6% without influence of the graft configuration. Postoperative follow-up was 13.6 ± 6.6 years and was 94% complete. The significant difference in patients' survival observed at 20 years in favor of GEA in unmatched groups (48 ± 4% vs 33 ± 6%, P < 0.001) was not confirmed in matched groups (41 ± 7% vs 36 ± 7%, P = 0.112). In multivariable Cox model analysis, the conduit used to RCA did not influence the long-term survival in matched groups, like no other graft configuration or operative parameter. Only complete revascularization remained predictor of survival (P = 0.016), with age (P < 0.0001), diabetes status (P = 0.007), and left ventricle ejection fraction (P < 0.0001). Long-term survival in patients undergoing BITA grafting is not affected by using GEA as third arterial conduit in alternative to SVG. Further studies are necessary to assess its impact on long-term cardiac events.

How decisive is the number of distal arterial anastomoses in coronary bypass surgery?

BACKGROUND: The benefit of arterial revascularization in coronary surgery remains controversial. The incremental value of additional grafts to the left internal thoracic artery (ITA) has been mainly assessed according to the number of arterial grafts, possibly limiting the detection of its actual impact. We analyzed the influence of the number of distal arterial anastomoses (DAA) performed on late mortality in patients having received from one to three arterial grafts. METHODS: Retrospective review of 3685 primary isolated coronary artery bypass grafting (CABG) performed from 1989 to 2014 was conducted with a 13-year mean follow-up. One arterial graft (SITA) was used in 969 patients, two arterial grafts, ITA or gastroepiploic artery (GEA), in 1883 patients (BITA: 1644; SITA+GEA: 239), and three arterial grafts in 833 patients (BITA+GEA). Totally, 795 patients (22%) received one DAA, 1142 patients (31%) two, 1337 patients (36%) three, and 411 patients (11%) four or more. A sub-group analysis was done in the 2104 patients with 3-vessel disease who received at least 2 arterial grafts. RESULTS: In this series the early mortality was 1.6% and it was not influenced by the surgical technique. Late mortality was significantly influenced by age, gender, heart failure, LV ejection fraction, diabetes status, complete revascularization, number of arterial grafts, number of DAA, both ITA, sequential ITA graft, GEA graft. In multivariable analysis with Cox regression model, the number of DAA was the only technical significant independent prognosis factor of late survival (p < 0.0001), predominant over both ITA, complete revascularization and number of arterial grafts. The impact of the number of DAA on survival was found discriminant from 1 to 3; after 3 there was no more additional effect. In 3-vessel disease patients who received at least 2 arterial grafts, the number of DAA remained a significant independent prognosis factor of late survival (p < 0.0001). CONCLUSIONS: The number of distal arterial anastomoses is an independent predictor of long-term survival, predominant over the number of arterial grafts and the completeness of the revascularization; higher the number, better the late survival. It is a strong support of the extensive use of arterial grafting in CABG.

[The interest of electroneuromyography in peripheral facial palsy]. / Apport de l'électroneuromyographie dans les paralysies faciales périphériques.

In case of peripheral facial palsy, electroneuromyogram of the facial nerve provides an indication of the nature (myelinic and/or axonal) and severity of nerve damage, thereby facilitating establishment of a prognosis, which is favorable for myelin damage, and guarded for severe axonal damage. The initial examination must be carried out during the second week. In case of severe axonal damage, examination results can be monitored at the third, and more particularly the sixth and the twelfth months. Stable neurophysiological data between the sixth and the twelfth months signal damage stability and open the way to possible palliative surgery. In the event of trigeminal damage, neurophysiological exploration furthers analysis of temporal muscle innervation. ENMG can confirm and precisely indicate peripheral hemifacial spasm.

Comparison of elastic scattering spectroscopy with histology in ex vivo prostate glands: potential application for optically guided biopsy and directed treatment.

The false-negative rate of ultrasound-guided sextant prostate biopsy has been estimated to be as high as 35 %. A significant percentage (10-35 %) of these prostate cancers diagnosed at a second or later attempt are high grade and, therefore, potentially lethal. We discuss the feasibility for performing optically guided biopsy using elastic scattering spectroscopy (ESS) to reduce sampling errors and improve sensitivity. ESS measurements were performed on 42 prostate glands ex vivo and correlated with standard histopathological assessment. Sliced glands were examined with wavelength ranges of 330-760 nm. The ESS portable system used a new fiber-optic probe with integrated cutting tool, designed specifically for ex vivo pathology applications. ESS spectra were grouped by diagnosis from standard histopathological procedure and then classified using linear support vector machine. Preliminary data are encouraging. ESS data showed strong spectral trends correlating with the histopathological assignments. The classification results showed a sensitivity of 0.83 and specificity of 0.87 for distinguishing dysplastic prostatic tissue from benign prostatic tissue. Similar results were obtained for distinguishing dysplastic prostatic tissue from prostatitis with a sensitivity and specificity of 0.80 and 0.88, respectively. The negative predictive values obtained with ESS are better than those obtained with transrectal ultrasound (TRUS)-guided core-needle biopsy.

Aflatoxins in peanut butter in Khartoum State, Sudan.

Forty-three peanut butter samples from Khartoum State, Sudan, were analyzed for aflatoxins (AFs, AFB1 + AFB2 + AFG1 + AFG2) using high performance liquid chromatography (HPLC) with fluorescence detection after extraction with methanol:water (8:1, v/v) and clean-up using chloroform. All samples were contaminated with AFs, with total AF levels ranging between 26.7 and 853 µg/kg, and a mean total AF level of 287 ± 200.5 µg/kg. The highest concentrations were found for AFB1, (28 positive samples, maximum 534 µg/kg), while AFG1 was most frequently detected (43 positive samples, maximum 401 µg/kg). AFB2 (42 positive samples, maximum 3.2 µg/kg) and AFG2 (4 positive samples, maximum 30 µg/kg) were also present in these samples. The mean AF contamination levels found in this study exceeded by far all international regulations concerning maximum levels for this group of toxins. From the data, it is concluded that the levels of AF contamination in peanut butter from the Kartoum area are quite alarming, and may pose serious health hazards to consumers. Therefore, an intervention strategy to manage AF in peanut butter is urgently needed.

[Fat tissue transplant: restoration of the mammary volume after conservative treatment of breast cancers, clinical and radiological considerations]. / Greffe de tissu adipeux: restauration du volume mammaire après traitement conservateur des cancers du sein, aspect clinique et radiologique.

The aim of this study is to evaluate fat tissue graft as a treatment of sequelae of breast cancer conservative surgery. MEANS AND METHODS: This prospective study during a nine-month period concerned 15 patients with breast cancer conservative treatment sequelae. Fat tissue has been injected at the site where the tumorectomie and subsequent radiotherapy had been performed. A mammographic and photographic checkup along with the patients' subjective evaluation were done before the operation and after the operation with a one-month, three-month, and nine-month follow-up. An objective analysis of the results was done by a panel from the pictures of the ninth month's follow-up. Preoperative and postoperative mammary volumes were calculated by a CT scan using a 3D program. RESULTS: Mean fat tissue injected was 63.3cc. Mean patients' satisfaction grade was 8.1/10 at one month and 6.7/10 at nine months. The estimation of the resorption at nine months was 52.6% according to the patients while announced at 47.5% with the CT scan. Eighty percent of patients estimated the operation as "light" and 60% would be ready to have another injection. Skin tissue quality was enhanced and only one infection has been stated. Two-thirds of postoperative mammographies are still ACR 2 and one-third of the patients have had cytosteatonecrosis. CONCLUSION: This fat tissue graft technique on irradiated skin for the correction of tumorectomy sequelae brings a simple and efficient solution, which is radiologically reliable and satisfying for the patients.

Enhanced levels of the aroma and flavor compound S-linalool by metabolic engineering of the terpenoid pathway in tomato fruits.

The aromas of fruits, vegetables, and flowers are mixtures of volatile metabolites, often present in parts per billion levels or less. We show here that tomato (Lycopersicon esculentum Mill.) plants transgenic for a heterologous Clarkia breweri S-linalool synthase (LIS) gene, under the control of the tomato late-ripening-specific E8 promoter, synthesize and accumulate S-linalool and 8-hydroxylinalool in ripening fruits. Apart from the difference in volatiles, no other phenotypic alterations were noted, including the levels of other terpenoids such as gamma- and alpha-tocopherols, lycopene, beta-carotene, and lutein. Our studies indicate that it is possible to enhance the levels of monoterpenes in ripening fruits by metabolic engineering.

Acetyl-coa: alcohol acetyltransferase activity and aroma formation in ripening melon fruits.

Melon varieties (Cucumis melo L.) differ in a range of physical and chemical attributes. Sweetness and aroma are two of the most important factors in fruit quality and consumer preference. Volatile acetates are major components of the headspace of ripening cv. Arava fruits, a commercially important climacteric melon. In contrast, volatile aldehydes and alcohols are most abundant in cv. Rochet fruits, a nonclimacteric melon. The formation of volatile acetates is catalyzed by alcohol acetyltransferases (AAT), which utilize acetyl-CoA to acetylate several alcohols. Cell-free extract derived from Arava ripe melons exhibited substantial levels of AAT activity with a variety of alcohol substrates, whereas similar extracts derived from Rochet ripe melons had negligible activity. The levels of AAT activity in unripe Arava melons were also low but steadily increased during ripening. In contrast, similar extracts from Rochet fruits displayed low AAT activity during all stages of maturation. In addition, the benzyl- and 2-phenylethyl-dependent AAT activity levels seem well correlated with the total soluble solid content in Arava fruits.

A recurrent valpha17/vbeta10 TCR-expressing T cell clone is involved in the pathogenicity of collagen-induced arthritis in DBA/1 mice.

Collagen-induced arthritis (CIA) is an experimental model that mimics clinical and histological features of rheumatoid arthritis. In this disease, a crucial role in initiating the pathological changes has been assigned to T lymphocytes expressing the Th1 phenotype. Aiming at identifying type II collagen (CII)-specific T cells involved in CIA, T cell clones were generated in vitro from the lymph nodes (LN) of CII-immunized DBA / 1 mice. In three independent experiments, we repeatedly isolated CD4(+) Th1 clones recognizing the immunodominant epitope in the CB11 fragment of bovine CII and expressing a unique alpha betaTCR produced by the rearrangement of Valpha17/Jalpha20 and Vbeta10/Dbeta1.1/Jbeta2.5 gene segments. By reverse transcriptase-PCR, we demonstrated the presence of mRNA transcripts specific for the beta complementary-determining region 3 of this clonotype in the LN of the majority (73%) of mice with CIA whereas it was never detected in control animals. When transferred to CII-immunized DBA/1 mice, this recurrent Th1 clone augmented the incidence, aggravated significantly the clinical signs of CIA and greatly enhanced the anti-CII antibody response. Altogether, these results provide evidence that a CD4(+) Th1 clone belonging to the public arm of the response toward the immunodominant epitope of CII is involved in the cascade of events leading to CIA.

Induction of experimental autoimmune thyroiditis by heat-denatured porcine thyroglobulin: a Tc1-mediated disease.

Recent studies have shown that denatured exogenous antigens can prime cytotoxic T lymphocytes (CTL). To assess the contribution of CTL to experimental autoimmune thyroiditis (EAT), porcine thyroglobulin (pTg) was heat-denatured (hdpTg) and injected i.v. into CBA/J mice, without the aid of adjuvants. Both lymphocytic infiltrations of the thyroid glands and levels of Tg-specific CTL were similar to those found in conventional EAT induced by Tg and adjuvants. In contrast, proliferative responses could not be detected, and titers of antibodies to pTg were 20 times lower. These EAT-inducer CTL belong to the CD8+ cell subset and exerted their thyroiditogenic potential through release of IFN-gamma. We conclude that hdpTg-induced EAT is mediated by type 1 cytotoxic T cells (Tc1).

Determination of endogenous porphyrins and the maximal HpD tumor/normal skin ratio in SKH-1 hairless mice by light induced fluorescence spectroscopy.

The treatment of skin tumors is an application of photochemotherapy (PCT) which involves an initial administration of a photosensitizer (PS) followed by irradiation with a light beam that causes the PS to produce cytotoxic oxygen species within the tumors. As the PS is also present in normal skin, it is necessary to know how it is distributed between the two tissues. In this study, we have used SKH-1 hairless mice bearing papillomas or carcinomas chemically induced. The biodistribution of hematoporphyrin derivative (HpD) and the tissue autofluorescence measurements were studied by light induced fluorescence spectroscopy. The tumor and normal autofluorescence spectra measured on control mice with papillomas or carcinomas had a very similar shape. However, the principal endogenous porphyrin peak at about 630 nm showed a fluorescence signal amplitude 2 (for papilloma) and 1.5 (for carcinoma)-fold higher than the one found for the normal skin. Moreover, the fluorescence intensity of carcinoma spectrum is 1.4-fold lower than the one of papilloma spectrum at 630 nm. The tissue autofluorescence can be used to distinguish tumor from normal skin and benign from malignant tumor. This difference in fluorescence intensity at 630 nm was directly related to the concentration of endogenous porphyrins in the tumor. Fluorescence intensity ratios between tumor and normal skin were measured 4, 8, 24, 48, 72 and 96 hours after intraperitoneal injection of HpD (5 mg/kg body weight). The best tumor/normal skin ratio was 6.2 for HpD and the time required to reach this ratio was 48 h. HpD showed a moderate selectivity since the ratio was higher than 1 during the four first days. Photodynamic therapy with the same dose of HpD used in this biodistribution study must also be carried out to verify that the maximal tumor/skin ratio corresponds to the maximal efficiency of HpD.

Conversion in vivo from an early dominant Th0/Th1 response to a Th2 phenotype during the development of collagen-induced arthritis.

Over the past decade, the central role of T cells in the process of collagen-induced arthritis (CIA) has been extensively documented. The inflammatory features of CIA and its successful modulation after treatment in vivo with Th2 lymphokines, known to down-regulate proinflammatory cytokines, classify CIA as a Th1-mediated disease. However, no direct evidence for the presence of the different T helper subsets has been obtained. To identify the collagen-specific CD4+ T cell subset(s) developing during the course of CIA, lymph nodes from susceptible DBA/1 mice (H-2q) were harvested at different times after injection of bovine type II collagen in Freund's complete adjuvant and checked by enzyme-linked immunospot assay for the production of interferon (IFN)-gamma and interleukin (IL)-4. The results clearly showed that type II collagen-specific T cells secreting either IFN-gamma, IL-4, or both, develop early in vivo, before the onset of arthritis: the number of IFN-gamma-secreting cells was already maximal 15 days after immunization, whereas more IL-4-secreting cells were found at day 30, just before the onset of clinical arthritis. Another strategy was to establish collagen-specific CD4+ T cell lines and sublines in vitro and to analyze their lymphokine secretion pattern. Lines generated 8 days after immunization displayed a mixed lymphokine secretion pattern characteristic of Th0 cells or of a mixture of Th1 and Th2 cells. After limiting dilution of a day 8 line, 60% of the growing sublines were Th0-like (secreting IFN-gamma, IL-4, and IL-5), and 25% were Th1 (secreting IFN-gamma). By day 25 post-immunization, 33% of the generated sublines were Th0-like, 11% Th1, and 56% Th2 (secreting IL-4 and IL-5). Moreover, all the sublines raised from the lymph nodes of arthritic mice harvested at day 55 secreted high amounts of Th2 lymphokines, and only 3 out of 14 also produced some IFN-gamma. This study demonstrates that during the course of CIA the collagen-specific CD4+ T cell response shifts in vivo from a dominant Th0/Th1 response to a clear Th2 phenotype. These results contribute to our understanding of the collagen-specific CD4+ T helper subsets which develop during the induction and clinical phases of CIA.

High susceptibility to collagen-induced arthritis in mice lacking IFN-gamma receptors.

Collagen-induced arthritis (CIA), an animal model for rheumatoid arthritis, is induced in DBA/1 (H-2q) mice following immunization with type II collagen (CII) in CFA. Since we have previously shown that IFN-gamma exerts a biphasic effect during the evolution of CIA in DBA/1 mice, we analyzed the development of this disease in mice with a disruption of the IFN-gamma receptor gene (IFN-gammaR(0/0)). Mutant mice were interbred with the DBA/1 strain to yield IFN-gammaR(0/0) mice expressing the H-2q haplotype. In three consecutive experiments, IFN-gammaR(0/0) male mice were found to exhibit severe clinical and histologic arthritis with an average incidence of 88.5 vs 94.1% for the wild DBA/1 strain. Notably, onset of clinical symptoms occurred significantly earlier than in DBA/1 mice. Although of a lower magnitude than in males, CIA also developed early in IFN-gammaR(0/0) female mice and with higher clinical severity than in control DBA/1 females. Immunization of knockout mice with CII resulted in the generation of CII-specific T cells belonging to the Th1 phenotype that recognize the same immunodominant peptides as do DBA/1 mice. CIA in IFN-gammaR(0/0) mice was associated with a down-regulation of the CII-specific IgG response, and this impairment was essentially due to a strong reduction of Abs of the IgG2a isotype. Taken together, our findings provide evidence that IFN-gammaR deficiency in DBA/1 mice leads to the occurrence of severe CIA with an accelerated onset compared with that in wild-type mice, indicating that the proinflammatory action of IFN-gamma has been bypassed in the IFN-gammaR(0/0) mice.

Determination of the maximal tumor/normal skin ratio after HpD or m-THPC administration in hairless mouse (SKh-1) by fluorescence spectroscopy--a non-invasive method.

Two major steps in our study on the treatment of skin tumors by photochemotherapy (PCT) were the development of a skin tumor model in hairless mice by chemical carcinogenesis and by the use fluorescence spectroscopy, a semi-quantitative and non-invasive method, to determine the time after i.p. injection of photosensitizer when the tumor/normal skin ratio is the highest. Carcinogenesis provided mice bearing many benign papillomas and these were used to determine the tumor/normal skin ratios of two photosensitizers by fluorescence spectroscopy. Hematoporphyrin derivative (HpD) (5 mg/kg body weight) and m-tetra(hydroxyphenyl)-chlorin (m-THPC) (0.3 mg/kg body weight) were injected, and fluorescence measured at 4, 8, 24, 48, 72 and 96 h after injection. The tumor/normal skin ratio was 6.2 for HpD and 5.1 for m-THPC. The times required to reach these ratios were 48 h for HpD and 72 h for m-THPC. Published reports indicate that m-THPC gives a much higher tumor/normal skin ratio than HpD. These results must be confirmed by organic extraction. Photodynamic therapy with the same doses of HpD and m-THPC used in this pharmacokinetic study must also be carried out to compare the toxicities of the two photosensitizers and to determine which is best for this type of tumor.

Collagen-induced arthritis in DBA/1 mice: cytokine gene activation following immunization with type II collagen.

Immunization of DBA/1 mice with bovine type II collagen (CII) in complete Freund's adjuvant (CFA) leads to collagen-induced arthritis as evidenced by joint inflammation. In this study, reverse transcription-polymerase chain reaction (RT-PCR) was used to demonstrate the activation of genes encoding for IL-2, IFN-gamma, and IL-10 in the lymph nodes from both CII-immunized and control CFA-immunized DBA/1 mice, at Days 10, 40, and 70 after immunization, in the absence of any IL-5 or IL-13 transcription. By quantitative RT-PCR, the levels of IFN-gamma mRNA in response to CII could not be quantitatively differentiated from the IFN-gamma transcribed in response to CFA alone. In the joints of CII-immunized mice, IL-1beta and IL-10 mRNA were found in the absence of IL-5 or IFN-gamma. Synovial IL-1beta and IL-10 were expressed most strongly at the time of clinical symptoms, 40 days after immunization. Together, these findings suggest that immunization with CII in CFA induces a type 1 response against the adjuvant, giving a cytokine environment which influences the T cells responding to CII to become type 1 T cells. This is manifested here by the appearance of gene activation in synovial tissue of collagen-immunized mice, but not in adjuvant-immunized control animals.

MTS-32 monoclonal antibody defines CD4+8- thymocyte subsets that differ in their maturation level, lymphokine secretion, and selection patterns.

We have previously described MTS-32 as identifying an Ag on both thymic stromal cells and thymocytes. In contrast with CD4+8+ and CD4-8+ thymocytes, of which the vast majority are MTS-32+, a notable subset of CD4+8- thymocytes is MTS-32-. Here we show that with regard to heat-stable Ags, Qa-2, and CD69 expression CD4+8- MTS-32- thymocytes are phenotypically enriched in mature cells when compared with their MTS-32+ counterparts. Moreover, sorted CD4+8- MTS-32+ thymocytes are unable to respond to anti-CD3 cross-linking, whereas MTS-32- CD4+8- thymocytes respond to the same stimulus by producing IL-4, IL-5, IL-10, IFN-gamma, and trace amounts of IL-2. In addition, MTS-32- CD4+8- and CD4-8- TCR-alpha beta+ thymocytes differ in their TCR V beta repertoire on a Mls-1a selecting background. We therefore suggest that the MTS-32 ligand is involved in signals consecutive with TCR recognition in the thymus, i.e., selection, activation, and lymphokine production.

IL-4 plays a dominant role in the differential development of Tho into Th1 and Th2 cells.

We have analyzed the evolution of the pattern of lymphokine secretion by Th cell lines specific for either the synthetic terpolymer Glu60Ala30Tyr10 (GAT) or killed bacillus Calmette Guérin. When cultured in the presence of exogenous rIL-2 as a growth factor, GAT-specific Th cell lines secreted mainly IL-4, whereas bacillus Calmette Guérin-specific lines produced predominantly IL-2. However, culturing in the presence of rIL-4 or of anti-IL-4 mAb and rIL-2 led to the establishment of Th2-like and Th1-like lines, respectively, regardless of their Ag specificity. Inasmuch as we show that the proliferative response of mature Th1 and Th2 cells was identical in the presence of IL-4, these results indicate that IL-4 influences the development of Th cell subsets. To understand the mode of IL-4 action, we isolated immature GAT-specific Tho clones able to secrete IL-2 and IL-4. Two types of Tho cells were isolated: ThoA cells that secreted IL-2 and IL-4, but not IFN-gamma, and ThoB cells that secreted IL-2, IL-4, and IFN-gamma. We show for the first time that such cells are indeed Th precursors able to differentiate into Th1 or Th2 cells. We demonstrate that IL-4 positively and negatively controls the differentiation of Tho cells into Th2 and Th1 cells, respectively. When cultured in rIL-4, Tho cells stop secreting IL-2 and IFN-gamma, but maintain IL-4 secretion. Moreover, endogenous IL-4 produced by Tho cells has similar effects: when cultured in rIL-2 alone, Tho cells either keep their immature phenotype or become Th2 cells, but do not become Th1 cells. In contrast, neutralization of secreted IL-4 completely prevents the differentiation of Tho into Th2 cells, but permits the development of Th1 cells. The presence of exogenous IFN-gamma does not affect the development of Tho into Th1 and Th2 cells, because it does not modify either mode of IL-4 action. However, it influences the ratio between the two types of Tho cells: when IL-4 is neutralized, added IFN-gamma can induce IFN-gamma secretion by ThoA cells and thereby facilitate their passage into ThoB cells. Taken together, our results demonstrate that IL-4, in addition to mediating T cell growth, is a principal factor that controls the differential development of Tho cells into Th1 and Th2 cells.

IL-4, but not IL-5, can act synergistically with B cell activating factor (BCAF) to induce proliferation of resting B cells.

B cell activating factor (BCAF) was initially identified in the supernatant of the murine T helper cell clone 52-3 (52-3 SN) because of its ability to promote activation and proliferation of resting B cells in the absence of any other costimulus. In this paper, we show that 52-3 T helper cells also secrete IL-4 and IL-5 and we have analyzed the influence of these two lymphokines on B cell proliferation induced by BCAF-containing 52-3 SN. Using the neutralizing anti-IL-4 monoclonal antibody 11B11, we observed partial inhibition of B cell proliferation. 52-3 SN free of IL-4 prepared using an immunoabsorbent column was still able to induce significant B cell proliferation. Although recombinant IL-4 alone does not induce B cell proliferation, it increased the proliferation induced by IL-4-free 52-3 SN. Kinetic studies showed that IL-4 is required at the start of B cell cultures in order to exert optimal synergistic effects. In contrast, anti-IL-5 monoclonal antibody NC17 did not affect the B cell proliferative activity of 52-3 SN whether or not IL-4 was present. When 52-3 SN was tested on dextran-sulfate-activated B cells, IL-5 and BCAF activities were detected but only the IL-5 activity was neutralized by monoclonal antibody NC17. These results demonstrate that (i) BCAF-containing SN can induce proliferation of resting B cells independently of IL-4 and IL-5, and (ii) IL-4, but not IL-5, can act synergistically with BCAF to induce B cell proliferation.

Structural requirements for the induction of "immunological castration" by linear monomeric LHRH-lys-MDP administered in saline.

It was previously shown that "castration" could be obtained in male mice by immunizing them in saline with a conjugate referred to as LHRH-Lys-MDP and containing the decapeptide hypothalamic hormone LHRH covalently linked to the adjuvant glycopeptide MDP-Lys. Since coupling was made using carbodiimide, it could have produced oligomers or isomers as well as monomers. In the present investigation male and female mice were immunized in saline with a linear monomeric MDP linked LHRH molecule obtained by total synthesis. Histological studies showed gonadal alterations in both male and female mice. The study of analogs provided a correlation between the "castrative" activity of LHRH-Lys-MDP and its chemical and antigenic structures. However, because LHRH antibody levels were not very high, mechanisms other than antibody response are discussed. Such totally synthesized molecules including a safe adjuvant could make a clinical use of LHRH immunization possible in endocrine-dependent cancers.

Covalent linkage of the synthetic adjuvant MDP to the synthetic polypeptide (T,G)-A-L changes the specificity of the immune response at the T and B cell level.

It is now well established that the synthetic molecule MDP (N-acetylmuramyl-L-alanyl-D-isoglutamine) can be a good adjuvant of immunity when covalently linked to antigen. The question raised in this work is whether conjugation of antigen to the immunomodulatory molecule MDP can modify the specificity of the antibodies and T cells induced following immunization. Using the well characterized synthetic polypeptide antigen, poly(L-Tyr,L-Glu)-poly(DL-Ala)--poly(L-Lys) [(T,G)-A--L], we show that immunization of C57B1/6 (H-2b) mice with MDP-(T,G)-A--L conjugate elicits at least two types of antibody directed against the poly(DL-Ala)--poly(L-Lys) (A--L) part of the antigen, and against new determinant(s) formed by MDP and a portion of the (T,G)-A--L molecule. Interestingly, the poly-(L-Try L-Glu) side chains thought to constitute the major antigenic determinants of the (T,G)-A--L molecule were not recognized. Lymph node cells from (T,G)-A--L immunized mice can be equally well stimulated in vitro by (T,G)-A--L or by MDP-(T,G)-A--L, whereas lymph node cells from MDP-(T,G)-A--L primed animals can be stimulated only when challenged by the conjugate used for immunization, and not by the free synthetic polypeptide (T,G)-A--L. The data presented here show that the coupling of a low mol. wt molecule such as MDP (mol. wt approx. 500) to an antigen can greatly modify the immune response directed against this antigen. Furthermore, (1) different antibody specificities are elicited depending upon whether the priming is done with free MDP and antigen or with MDP covalently linked to the antigen; (2) although still accessible on the conjugate, an epitope which represents the major antigenic determinant on the free polypeptide appears to be silent when presented on the conjugate; and (3) new determinant(s) formed by the chemical linkage of the polypeptide to the synthetic adjuvant are involved in the priming of T cells.