Prognostic value of postoperative carcinoembryonic antigen concentration and extent of invasion of resection margins after hepatic resection for colorectal metastases.

OBJECTIVE: To evaluate the prognostic value of postoperative concentration of carcinoembryonic antigen (CEA) and extent of surgical margins after resection of liver metastases from colorectal cancer. DESIGN: Retrospective study. SETTING: Teaching hospital, Switzerland. SUBJECTS: 49 patients with hepatic metastases after primary colorectal cancer. INTERVENTIONS: Resection of hepatic metastases MAIN OUTCOME MEASURES: Assessment of prognostic value of variables by univariate and multivariate analysis. RESULTS: Median survival was 24 months (range 5-86 months). Resection margins were clear (> 1-cm) in 10, close (< 1-cm) in 25 and invaded in 9 patients. On univariate analysis, a postoperative concentration of CEA of <4ng/ml was correlated with prolonged survival (p < 0.001), but the width of the resection margin was not of prognostic importance. There was no correlation between width of resection margins and postoperative concentration of CEA (p = 0.5). On multivariate analysis, postoperative concentrations of CEA of 4 ng/ml or more were associated with increased risk of death (relative risk 7.3; 95% confidence interval (CI) 2.8-18.7, p < 0.001). CONCLUSION: Postoperative CEA offers better prognostic discrimination than the width of resection margins after resection of liver metastases from colorectal tumours. Some patients with invaded resection margins did survive for 3 years, but no patient did whose CEA concentration was 4 ng/ml or more. The definition of a potentially curative hepatic resection should include a postoperative CEA concentration of <4 ng/ml (within the reference range).

Maturation of marginal zone and follicular B cells requires B cell activating factor of the tumor necrosis factor family and is independent of B cell maturation antigen.

B cells undergo a complex series of maturation and selection steps in the bone marrow and spleen during differentiation into mature immune effector cells. The tumor necrosis factor (TNF) family member B cell activating factor of the TNF family (BAFF) (BLyS/TALL-1) plays an important role in B cell homeostasis. BAFF and its close homologue a proliferation-inducing ligand (APRIL) have both been shown to interact with at least two receptors, B cell maturation antigen (BCMA) and transmembrane activator and cyclophilin ligand interactor (TACI), however their relative contribution in transducing BAFF signals in vivo remains unclear. To functionally inactivate both BAFF and APRIL, mice transgenic for a soluble form of TACI were generated. They display a developmental block of B cell maturation in the periphery, leading to a severe depletion of marginal zone and follicular B2 B cells, but not of peritoneal B1 B cells. In contrast, mice transgenic for a soluble form of BCMA, which binds APRIL, have no detectable B cell phenotype. This demonstrates a crucial role for BAFF in B cell maturation and strongly suggests that it signals via a BCMA-independent pathway and in an APRIL-dispensable way.

Assessing ageing of individual T lymphocytes: mission impossible?

Effector T lymphocytes are the progeny of a limited number of antigen-specific precursor cells and it has been estimated that clonotypic human T cells may expand million fold on their way reaching high cell numbers that are sufficient for immune protection. Moreover, memory T cell responses are characterized by repetitive expansion of antigen-specific T cell clonotypes, and limitations in the proliferative capacity could lead to immune senescence. Because telomeres progressively shorten as a function of cell division, telomere length is a powerful indicator of the replicative in vivo history of human T lymphocytes. In this review, we summarize observations made over the last decade on telomere length dynamics of well-defined T cell populations derived from healthy donors and patients with infectious disease or cancer. We focus on T cell differentiation, T cell ageing, and natural and vaccine induced immune responses. We also discuss the scientific evidence for in vivo replicative senescence of antigen-specific T cells, and evaluate the available methods for measuring telomere lengths and telomerase activity, and their potential and limitations to increase our understanding of T cell physiology.

The serological differentiation of acute and chronic schistosomiasis japonica using IgA antibody to egg antigen

Two groups of Schistosoma japonicum infected patients (acute and chronic ) and non-infected individuals were studied using IgA antibody to egg antigen (SEA) and IgG and IgM antibodies to keyhole limpet haemocyanin (KLH). The means and standard deviation of the optical density in ELISA of acute, chronic and negative groups for IgA anti-SEA were 583±124.7, 98.2±78.8 and 82.2±39. 3, respectively. There was a statistically significance between acute patients and chronic patients (P<0.01). The means and standard deviation of IgG and IgM antibodies to KLH were 501.5±150.6, 113.0±79.1, 28.8±56.3 and 413.6±148.5, 70.2±14.8, 65.3±45.3, respectively. The detection results of IgA to SEA compared with the IgG and IgM to KLH did not demonstrate a significant difference (P>0.01). The sensitivities of IgA to SEA and IgG and IgM antibodies to KLH for the detection of acute infection were 95.24%, 90.48% and 85.71%, respectively. Therefore, this study showed that the detection of IgA to SEA is also a useful new method for the serological differentiation of acute and chronic schistosomiasis japonica in humans.

Seroepidemiological Studies of Cutaneous Leishmaniasis in the Campeche State of México

Seroepidemiological studies of cutaneous leishmaniasis were carried out on 169 individuals in a rural area of the Campeche state of México. Fifty showed cutaneous lesions suggestive of leishmaniasis, 70% were parasite positive and 96% skin test positive. An overall 40% positivity to skin test with Montenegro's antigen was found. Most of the affected individuals were males from 11 to 30 years-old. Antibodies were determined by immunofluorescent antibody test (IFA) and by Western blot. Two antigen preparations were used, one from a Leishmania mexicana strain which produced localized cutaneous leishmaniasis (LCL) and the other from a diffuse cutaneous leishmaniasis (DCL). In the general population from the area of study 19% gave positive IFA tests with DCL antigen and 20% with LCL antigen while for the patients 67% gave positive IFA tests with DCL and 71% with LCL. By Western blot analysis most of the patients recognized more antigens in the DCL than in the LCL strain. In the DCL strain 78% of patients recognized a 105 kDa, 34% a 139 kDa, 28% a 117 kDa and 26% a 205 kDa MW antigen. In the LCL strain 40% of patients recognized a 205 kDa and 22% a 175 kDa antigens

Immune Response to Trypanosoma cruzi Shed Acute Phase Antigen in Children from an Endemic Area for Chagas' Disease in Bolivia

A field study of the immune response to the shed acute phase antigen (SAPA) of Trypanosoma cruzi was carried out in the locality of Mizque, Cochabamba department, Bolivia. Schoolchildren (266), with an average of 8.6 ± 3.6 years, were surveyed for parasitological and serological diagnosis, as well as antibodies directed against SAPA using the corresponding recombinant protein in ELISA. The antibodies against SAPA were shown in 82% of patients presenting positive serological diagnosis (IgG specific antibodies). The positive and negative predictive values were 0.88. Antibodies anti-SAPA were shown in 80.8% of the chagasic patients in the initial stage of the infection (positive IgM serology and/or positive buffy coat (BC) test) and in 81.4% of the patients in the indeterminate stage of the infection (positive IgG serology with negative BC and IgM tests). These results show that the anti-SAPA response is not only present during the initial stage of the infection (few months) but extends some years after infection

Detection of the common acute lymphoblastic leukemia antigen in the serum of leukemia patients.

The common acute lymphoblastic leukemia antigen (CALLA) has been detected in biological fluids using a radioimmunoassay based on the inhibition of binding of 125I-labeled monoclonal anti-CALLA antibody to glutaraldehyde-fixed NALM-1 cells. With this assay, we showed first that CALLA was released in culture fluids from NALM-1 and Daudi cell lines but was absent from culture fluids from CALLA negative cell lines. Then, we found that the sera of 34 out of 42 patients (81%) with untreated common acute lymphoblastic leukemia (c-ALL) contained higher CALLA levels than any of the 42 serum samples from healthy controls. The specificity of these results was further demonstrated by testing in parallel the sera from 48 patients with CALLA negative leukemias, including 26 acute myeloid leukemia (AML), 12 T-cell acute lymphoblastic leukemia (T-ALL), and 10 acute undifferentiated leukemia (AUL). All of these sera gave negative results, except for one patient with AUL, who had a significantly elevated circulating CALLA level, and one patient with AML, who had a borderline CALLA level, 3 SD over the mean of the normal sera. Preliminary results suggest that circulating CALLA is associated with membrane fragments or vesicles, since the total CALLA antigenic activity was recovered in the pellet of the serum samples centrifuged at 100,000 g. In addition, the CALLA-positive pellets contained an enzyme considered as a membrane marker, 5'-nucleotidase. Evaluation of the clinical importance of repeated serum CALLA determinations for the monitoring of c-ALL patients deserves further investigation.

The Role of Protein Kinases in Antigen-activation of Peripheral Blood Mononuclear Cells of Schistosoma mansoni Infected Individuals

T cell recognition of antigens displayed on the surface of antigen presenting cell results in rapid activation of protein tyrosine kinases and kinase C. This process leads to second messengers, such as inositol phosphates and diacylgycerol, and phosphorylation of multiple proteins. The role of different protein kinases in the activation of peripheral blood mononuclear cells (PBMC) from Schistosoma mansoni infected individuals was evaluated using genistein and H-7, specific inhibitors of protein tyrosine kinase and kinase C, respectively. Our results showed that proliferation in response to soluble egg antigen or adult worm antigen preparation of S. mansoni was reduced when PBMC were cultured in presence of protein kinase inhibitors. Using these inhibitors on in vitro granuloma reaction, we also observed a marked reduction of granuloma index. Taken together, our results suggest that S. mansoni antigen activation of PBMC involves protein kinases activity

Evidentiation of Paramyosin (Sm-97) as a Modulating Antigen on Granulomatous Hypersensitivity to Schistosoma mansoni Eggs

A Schistosoma mansoni adult worm anionic fraction (PIII) has previously been shown to protect mice against challenge infection and to reduce pulmonary and hepatic granulomatous hypersensitivity. Serum from PIII-immunized rabbit was used to screen a lgt11 cDNA library from S. mansoni adult worm in order to identify antigens capable of modulating granulomatous hypersensitivity. We obtained four clones with 400 (Sm-III.11), 900 (Sm-III.16), 1100 (Sm-III.10) and 1300 (Sm-III.12) bp of length. All clone-specific antibodies were able to recognize most of the PIII components. The sequence analysis showed that these clones presented high homology with S. mansoni paramyosin (Sm-97). These findings ascribe a new function to this antigen with an important role in modulation of granulomatous hypersensitivity to S. mansoni eggs

Detachment of cell surface-bound anticarcinoembryonic antigen immune complexes by phospholipase C.

CEA as well as normal cross-reacting antigens (NCA) are fixed to the cell membrane via phosphatidylinositol (PI). To find out whether these antigens are internalized after antibody contact, acid pH desorption was compared to phospholipase C (PLC)-mediated cleavage of the antigen anchor. With the former procedure, marked differences in the desorbability of individual MAbs were noted, while PLC was able to cleave off surface-bound immune complexes irrespective of the MAb involved. From this it is concluded that internalization of MAb complexes of CEA/NCA, if occurring at all, is a low efficiency process.

Optimum in vitro expansion of human antigen-specific CD8 T cells for adoptive transfer therapy.

Increasing evidence suggests that adoptive transfer of antigen-specific CD8(+) T cells could represent an effective strategy in the fight against chronic viral infections and malignancies such as melanoma. None the less, a major limitation in the implementation of such therapy resides in the difficulties associated with achieving rapid and efficient expansion of functional T cells in culture necessary to obtain the large numbers required for intravenous infusion. Recently, the critical role of the cytokines interleukin (IL)-2, IL-7 and IL-15 in driving T cell proliferation has been emphasized, thus suggesting their use in the optimization of expansion protocols. We have used major histocompatibility complex (MHC) class I/peptide multimers to monitor the expansion of antigen-specific CD8 T lymphocytes from whole blood, exploring the effect of antigenic peptide dose, IL-2, IL-7 and IL-15 concentrations on the magnitude and functional characteristics of the antigen-specific CD8(+) T cells generated. We show here that significant expansions of antigen-specific T cells, up to 50% of the CD8(+) T cell population, can be obtained after a single round of antigen/cytokine (IL-2 or IL-15) stimulation, and that these cells display good cytolytic and interferon (IFN)-gamma secretion capabilities. Our results provide an important basis for the rapid in vitro expansion of autologous T cells from the circulating lymphocyte pool using a simple procedure, which is necessary for the development of adoptive transfer therapies.

Inhibition of antigen-induced T-cell clone proliferation by antigen-specific antibodies.

Attempts to inhibit the recognition of soluble antigens by T lymphocytes using antibodies specific for the antigen in question have been uniformally unsuccessful, in contrast to the observed specific inhibition of antibody generation by B cells. One exception is the unique situation whereby anti-hapten antisera inhibit the T-cell proliferative responses observed when hapten-specific T lymphocytes or clones are cultured with hapten-derivatized cells or proteins. The inability to inhibit T-cell functions by antigen-specific antibodies has been interpreted in several ways: (1) T cells possess a different repertoire from B cells; (2) the antibodies tested recognize epitopes present on the native antigen, whereas T cells recognize non-native (processed) structures; (3) the antigenic determinant(s) recognized by T cells on the surface of antigen presenting cells are either not accessible to antibodies, or are present in low amounts. The development of antigen-specific T-cell clones and monoclonal antibodies both specific for the same antigenic determinants now allows this question to be investigated definitively. Here, we report for the first time the specific inhibition of antigen-induced T-cell clone proliferation by a monoclonal antibody directed against the relevant soluble protein antigen.