Response of human lymphocytes to measles virus after natural infection

Gut microbial biomarkers for the treatment response in first-episode, drug-naïve schizophrenia: a 24-week follow-up study

Preclinical studies have shown that the gut microbiota can play a role in schizophrenia (SCH) pathogenesis via the gut-brain axis. However, its role in the antipsychotic treatment response is unclear. Here, we present a 24-week follow-up study to identify gut microbial biomarkers for SCH diagnosis and treatment response, using a sample of 107 first-episode, drug-naïve SCH patients, and 107 healthy controls (HCs). We collected biological samples at baseline (all participants) and follow-up time points after risperidone treatment (SCH patients). Treatment response was assessed using the Positive and Negative Symptoms Scale total (PANSS-T) score. False discovery rate was used to correct for multiple testing. We found that SCH patients showed lower α-diversity (the Shannon and Simpson's indices) compared to HCs at baseline (p = 1.21 × 10-9, 1.23 × 10-8, respectively). We also found a significant difference in β-diversity between SCH patients and HCs (p = 0.001). At baseline, using microbes that showed different abundance between patients and controls as predictors, a prediction model can distinguish patients from HCs with an area under the curve (AUC) of 0.867. In SCH patients, after 24 weeks of risperidone treatment, we observed an increase of α-diversity toward the basal level of HCs. At the genus level, we observed decreased abundance of Lachnoclostridium (p = 0.019) and increased abundance Romboutsia (p = 0.067). Moreover, the treatment response in SCH patients was significantly associated with the basal levels of Lachnoclostridium and Romboutsia (p = 0.005 and 0.006, respectively). Our results suggest that SCH patients may present characteristic microbiota, and certain microbiota biomarkers may predict treatment response in this patient population.

Alterations in cell-mediated immune response in subacute sclerosing panencephalitis

To investigate T cell responses in subacute sclerosing panencephalitis (SSPE), we analyzed proliferation and cytokine secretion of cells from 35 patients and 42 healthy controls (HC) in response to central nervous system (CNS) antigens. The proliferation in response to myelin basic protein (MBP), myelin oligodendrocyte-glycoprotein (MOG) and alphaB-crystallin did not differ between groups. There was a trend towards a decrease in IL-12 production in response to MBP and in vitro IL-12 secretion of SSPE patients to measles virus vaccine (MVV) was lower than controls. Proliferation, as well as IFN-gamma, IL-12 and IL-10 production in response to purified protein derivate (PPD) was impaired in SSPE patients. The results did not demonstrate any by-stander cellular response against myelin antigens, implicating that CNS is not a predominant target of an autoimmune response in SSPE. The recall responses were lower in SSPE as reported in measles before.

Development and durability of measles antigen-specific lymphoproliferative response after MMR vaccination

The correlates of long-term protection from measles infection are poorly understood. We followed the development of measles-specific antibody and lymphoproliferative (LP) responses in 60 children for 6 months after MMR vaccination. Prevaccine plaque reduction neutralization antibody (PRN Ab) values were low (mean+/-SEM 9.9+/-1. 1). Ninety-three percent (56/60) had excellent PRN values at 6 months (PRN 1816+/-207). Prevaccine LP activity was also low (stimulation index (SI)=1.4+/-0.1) but increased rapidly (SI 10. 7+/-4.5 at 2-3 weeks; p<0.05). However, only 61% (37/60) of the children had both significant cellular and antibody responses (SI>/=3 and PRN>/=120: Ab(hi)CMI(hi)). One child had a strong LP response (SI=6.7) despite little antibody production (PRN=19 at 6 months: Ab(lo)CMI(hi)). We also conducted a cross-sectional study in a separate group of 87 children 5-13 years after MMR vaccination. PRN values >/=120 were present in most children at 5-8 (n=28) and 9-13 years (n=59) after vaccination (PRN 550+/-120 and 360+/-60, respectively) but a significant minority had either undetected or 'subprotective' values (29 and 34%, respectively). LP responses (SI>/=3) were detectable in 19/28 (66%) and 36/59 (56%) of the children 5-8 and 9-13 years after vaccination (SI 11.4+/-2.4 and 7. 75+/-1.9, respectively). Almost two thirds (18/28) of the children in the cross-sectional study with low or absent antibody titers (PRN 41+/-6) had strong LP responses to measles antigens (SI 6.8+/-1.3). These data suggest that LP responses may be better sustained than antibody titers in some children. The susceptibility of Ab(lo)CMI(hi) children to infection and the value of the early LP response for predicting the durability of immunity remain to be determined.

Antigen-specific expansion of cytotoxic T lymphocytes in acute measles virus infection

Skewing of the T-cell receptor repertoire of CD8(+) T cells has been shown in some persistent infections with viruses, such as human immunodeficiency virus, simian immunodeficiency virus, and Epstein-Barr virus. We have demonstrated that similar distortions also occur in nonpersistent measles virus infection. In addition, two of four children immunized with live, attenuated measles virus showed larger and more persistent CD8(+) T-cell expansions than their naturally infected counterparts. The expanded lymphocyte populations were monoclonal or oligoclonal and lysed target cells infected with recombinant vaccinia virus expressing measles virus protein. These results demonstrate that the expansions of CD8(+) T lymphocytes are antigen driven.

Detection of acute measles infections by indirect and mu-capture enzyme immunoassays for immunoglobulin M antibodies and measles immunoglobulin G antibody avidity enzyme immunoassay

An avidity test for measles IgG was developed and applied to the study of IgG immunoglobulin maturation kinetics in follow-up sera from 12 patients with known acute primary and convalescent measles and sera from blood donors. The avidity of the IgG anti-measles responses was measured using the 8 M urea elution technique, the results being expressed as the percentage ratio between the test readings for eluted and noneluted samples. The IgG avidity results were compared with those of indirect and mu-capture IgM enzyme immunoassays. This test was capable of detecting low-avidity antibodies at the acute phase of measles up to 7 weeks, and increasing avidity through immunosaturation during the convalescent phase. The avidity in these samples did not reach the level found in the samples of the blood donors under the follow-up time. Although a limited number of serum samples was examined, the results suggest that the measles IgG avidity test is a powerful tool for differentiating primary measles infection from the convalescent phase.

Immune responses during measles virus infection

The characteristic disease features of measles--fever and rash--are associated with the immune response to infection and are coincident with virus clearance. MV-specific antibody and CD4 and CD8 T cell responses are generated and contribute to virus clearance and protection from reinfection. During this same phase of immune activation immunologic abnormalities are also apparent. There is a generalized suppression of cellular immune responses that may contribute to increased susceptibility to other infections. Autoimmune disease may appear in the form of acute disseminated encephalomyelitis. If virus-specific immune responses are inadequate infection may progress with pulmonary or CNS manifestations, but without a rash. The pathogenesis of the rare disease SSPE, that occurs many years after primary infection is not clear, but immune responses show increased antibody to measles and cellular immune responses similar to those seen after uncomplicated infection.

Immunosuppression after measles vaccination

The influence of conventional live attenuated measles vaccine on cellular immune responsiveness was investigated in Sweden and Guinea-Bissau. Sixteen children in a residential area in Bissau and 16 living in southern Stockholm were examined before and 8-10 days after vaccination. Lymphoproliferation was measured to concanavalin A (con-A), PPD and tetanus toxoid (TT) using a whole-blood 3H-thymidine incorporation assay. Stimulation indices were significantly lower after vaccination than before, in the case of con-A (p = 0.03) and TT (p = 0.01) in the Guinean children and in the case of PPD (p = 0.009) and TT (p = 0.03) in the Swedish children. Stimulation of lymphocytes from measles-immune children with measles antigens resulted in weak lymphoproliferative responses. These observations may be relevant to the increased mortality found in children immunized with high-titre measles vaccines, as compared to controls, in recent studies. The study confirms the applicability and usefulness under field conditions of the whole blood version of the thymidine incorporation assay.

Biochemical and biological activities of recombinant S1 subunit of pertussis toxin

degP-deficient strains of Escherichia coli grown in M-9 medium supplemented with ZnCl2 expressed the recombinant S1 subunit of pertussis toxin (rS1) in a form electrophoretically identical to the authentic S1 subunit. Subcellular fractionation showed that the full-length form of rS1 was membrane associated, while proteolytic fragments of rS1 were present in the periplasm. rS1 was extracted from outer membrane preparations with 8 M urea and purified by gel filtration chromatography. Purified rS1 ADP-ribosylated transducin at a similar molar efficiency relative to authentic pertussis toxin and, when associated with the native B oligomer of pertussis toxin, elicited Chinese hamster ovary cell clustering.

T-cell recognition of measles virus haemagglutinin studied in a mouse model

BALB/c mice were pretreated with cyclophosphamide and immunized 2 days later with inactivated, purified measles virus (MV) mixed with dimethyl dioctadecyl ammonium bromide (DDA). Seven days later, lymph nodes (LN) were removed and lymphocytes cultured in the presence of purified MV antigens. MV haemagglutinin (H) was found to be a major antigen responsible for proliferation of the lymphocytes. Incorporation of purified H into liposomes significantly enhanced the proliferative response compared with purified H alone. Response to MV nucleocapsid protein was only moderate, and insertion of this protein into liposomes did not improve the response. As an attempt to analyse T-cell epitopes of MV H, three synthetic peptides previously found to elicit a strong antibody response were used both as priming and stimulating antigens. None of the peptides was able to elicit a secondary response when MV-primed LN cells were stimulated in vitro. However, each peptide primed T cells for a secondary challenge with purified, inactivated MV, which was demonstrated by proliferation and a delayed-type hypersensitivity assay and also by transfer experiments with peptide-primed cells.

Immunosuppression by canine distemper virus: modulation of in vitro immunoglobulin synthesis, interleukin release and prostaglandin E2 production

In vitro or in vivo infection of canine mononuclear cells by canine distemper virus (CDV) in short-term microcultures resulted in suppression of lectin-induced 3H-thymidine incorporation. This suppressive effect was also evident in pokeweed mitogen-driven in vitro immunoglobulin synthesis and release. Lectin-induced interleukin-2 production by monocyte-depleted lymphocyte cultures was marginally affected by CDV, whereas interleukin-1 production by adherent mononuclear cells was significantly depressed. Monocyte cultures established from viremic dogs released prostaglandin (PG)E2. The results suggest that, in addition to a direct viral effect upon lectin responsive cellular population(s), CDV modulates monocyte functions by inhibition of interleukin-1 production and by enhancing PGE2 release.

Human cellular immune response to measles virus polypeptides

Measles virus polypeptides were separated by polyacrylamide gel electrophoresis and electroeluted from gel sections. The antigenicity of the polypeptides was determined by enzyme-linked immunosorbent assays. The ability of these measles virus antigens to stimulate lymphoproliferation was measured in both high- and low-responder individuals. In contrast to the low-responder lymphocytes which did not proliferate when stimulated with measles virus antigens, the high-responder lymphocytes proliferated when challenged with hemagglutinin, nucleocapsid-associated phosphoprotein, nucleocapsid protein, matrix protein, and fusion protein.

The lymphoproliferative response to measles virus in twins with multiple sclerosis

The cellular immune response to measles virus, as measured by lymphocyte proliferation in normal individuals, is considerably lower than that to mumps or vaccinia viruses, and stable multiple sclerosis patients do not differ significantly from the norm. The response to these viruses was studied in 28 twin sets both concordant and discordant for multiple sclerosis. Normal responses to mumps and vaccinia viruses occurred throughout. Seven affected twins manifested a persistently elevated response to measles virus, whereas the unaffected twins had a (normal) low response. The differences were unrelated to differences in T cell subsets, unusual kinetics of the response, or differential susceptibility of lymphocytes to the effects of measles virus infection in vitro. The specificity of the response resides in an E+ subpopulation, and the addition of low-responder E+ cells to high-responder E+ cells failed to identify an active low-responder suppressor population. These findings suggest the presence of clonally expanded measles-specific T cell populations in the high responders with multiple sclerosis.