Antiviral adoptive immunotherapy using antigen-specific T cells in allogeneic hematopoietic stem cell transplant recipients

Adoptive immunotherapy using antiviral T cells (AVT) obtained from healthy donors is one of the advanced approaches considered as a breakthrough in the treatment of refractory and severe viral infections that often accompany primary immunodeficiencies or allogeneic hematopoietic stem cell transplantations. The review describes nearly 30 years of the development of AVT to human cytomegalovirus, Epstein-Barr virus, human adenovirus, and human polyomavirus BK. The review introduces the basic methodological approaches to their production and summarizes the results from clinical studies that tested the safety and efficiency of the procedures used. Recent studies indicate that the treatment of viral infections by frozen AVT stored in banks could become a commonly available therapeutic modality.

[Genotyping of viral glycoprotein B (gB) in hematopoietic stem cell transplant recipients with active cytomegalovirus infection: analysis of the impact of gB genotypes on the patients' outcome]

AIM OF THE STUDY

Genetic variation of CMV strains may correlate with their pathogenicity for immunocompromised patients. On the basis of sequence variation in the UL55 gene encoding the most abundant viral envelope glycoprotein gB, CMV can be classified into four major gB genotypes. The aim of the study was the analysis of the distribution of gB genotypes in a cohort of haematopoietic stem cell transplant (HSCT) recipients and of the correlation of genetic polymorphisms with clinical outcomes and manifestation of CMV infection.

MATERIAL AND METHODS

Archived DNA isolates from consecutive blood samples of 53 adult allogeneic HSCT recipients with active CMV infection, transplanted in 2004-2005, were used for the genetic analysis. HCMV gB genotyping was performed by restriction fragment length polymorphism (RFLP) analysis and sequencing of the central variable region of UL55. The association of gB genotypes with selected clinical parameters was assessed by multivariate analysis after adjustment for graft donor type, HLA-matching and anti-thymocyte immunoglobulin (ATG) therapy.

RESULTS

gB1, gB2, gB3, and gB4 genotypes were detected in 30%, 17%, 26% and 4% of the patients, respectively. An atypical gB genotype was found in one patient. Co-infection with two or more gB genotypes was revealed in 17% of the patients. The distribution of gB genotypes did not vary in time, despite the fact that the patients transplanted in 2005 had more severe CMV infection with higher viral loads in the blood than those transplanted in 2004. gB1 was associated with a lower viral load (p = 0.046) and a milder course of symptomatic CMV infection, but with a higher rate of acute graft versus host disease (OR 3.4; p = 0.067). Pancytopenia was less frequent in the patients infected with gB3 (OR 0.09; p = 0.075). In contrast, gB2-infected patients had a worse outcome of CMV infection with a higher rate of organ involvement and were less responsive to antiviral therapy (OR 6.65 and 0.18; p = 0.15 and 0.12, respectively). The prognostic impact of co-infection with two or more gB genotypes was not shown.

CONCLUSIONS

gB genotype may have an impact on the course of CMV infection and its complications in HSCT recipients. Nevertheless, these results need to be tested on a larger group of patients in the context of genetic variability of other functionally important viral genes. The characterization of viral genetic factors determining CMV pathogenesis will be of relevance to the treatment of patients at high risk of CMV infection.

[Prevalence of glycoprotein B (gB) genotypes in the patients with high risk of symptomatic cytomegalovirus infection]

OBJECTIVES

Based on genetic variability of the dominant envelope glycoprotein (gB), human cytomegalovirus is classified into four major genotypes. The aims were to determine the prevalence of particular gB genotypes in Czech CMV-infected patients and to compare three groups of the patients with high risk of symptomatic CMV infection, i.e., haematopoietic stem cell transplant (HSCT) recipients, HIV-positive persons and infants.

MATERIAL AND METHODS

The study was performed on 134 archived CMV-positive DNA isolates from the patients tested in the National Reference Laboratory for Herpesviruses in 2004-2007. For genotyping, the variable part of gB was amplified and analysed using the restriction fragment length polymorphism (RFLP) method.

RESULTS

The most frequently detected genotype was gB1 (33%), followed by gB2 (29%), gB3 (18%) and gB4 (7%). However, the distribution of gB genotypes varied between groups of high-risk patients: gB2 dominated in HIV-positives (55%, p = 0.004), while gB3 was most common in HSCT recipients (26%, p = 0.03) and gB4 was relatively more frequent in infants (20%, p = 0.03). In HSCT recipients, we found increased frequency of gB3 (26%, p = 0.03) and co-infection with two or more gB genotypes (17%, p = 0.016).

CONCLUSIONS

The distribution of CMV gB genotypes from Czech CMV-infected patients is similar to that reported in other European countries or in the United States. Differences in the prevalence of CMV gB genotypes between groups of high-risk patients indicate variation in biological properties of particular gB genotypes, possibly resulting in distinct virulence, immunogenicity or epidemiological characteristics of circulating strains.

[Guidelines for the diagnosis and treatment of genital herpes in women]

Presented are draft guidelines for genital herpes (GH) in women. The text is concerned with the incidence, clinical picture, diagnosis, prevention, prophylaxis and therapy of genital HSV infection. The aim is to provide valuable information on the approach to both initial and relapsing GH, with attention being paid to risk factors such as immunosuppression or pregnancy. Also mentioned are procedures to decrease the risk of vertical transmission of HIV infection and adequate measures to prevent disseminated neonatal herpes infection.

Mumps Vaccination in the Czech Republic

I would like to take this opportunity to present a more complete picture of Czech mumps vaccine history.

[A simultaneous detection of Chlamydia pneumoniae and Chlamydia trachomatis DNA by real-time PCR]

STUDY OBJECTIVE

Design and validation of a real-time PCR assay for quantitative detection of C. pneumoniae and C. trachomatis in clinical specimens.

MATERIAL AND METHODS

A part of the 16S RNA gene was selected as the target sequence for amplification. The reaction product was cloned in the bacterial plasmid and a recombinant calibrator and a combined internal standard were prepared, usable in three different PCR assays. Archived DNA isolates from various clinical specimens, DNA isolates from other infectious agents and control samples for DNA detection, CT (QCMD) and CPN (Instand), were used for validation.

RESULTS

Reaction specificity and reproducibility were tested. The analytical sensitivity was set to 5-10 copies of the bacterial genome/reaction. As many as 105 DNA isolates from various types of clinical specimens (swabs, urine, peripheral blood and BAL fluid) were tested by real-time PCR and conventional PCR assays. The specimens that had not yielded concordant results were characterized by a third independent amplification test. The sensitivity and specificity of real-time PCR were 89% and 100%, respectively. The assay is suitable for both screening and diagnosis of Chlamydia.

Prevalence of active infection with Chlamydia pneumoniae and human cytomegalovirus in patients with type II diabetes mellitus

By promoting the inflammatory process in the arterial wall, Chlamydia pneumoniae (CPN) and human cytomegalovirus (CMV) participate in the pathogenesis of cardiovascular disease (CVD). Since patients with diabetes mellitus (DM) are at high risk of CVD, we studied markers of CMV and CPN infection in DM patients as possible predictors of cardiovascular complications. The seroprevalence rates of CMV in 44 DM patients and matched controls were 74 and 88%, respectively. Compared with controls, patients showed lower titers of IgG against CMV (p < 0.001) and higher titers of genus-specific IgA against CPN (p = 0.006). The titers of genus-specific IgG and prevalence rates of type-specific anti-CPN IgA, IgG or IgM were similar in both DM patients and controls. Serological markers of either active or recent CPN infection were detected in 54% of patients and 59% of controls. However, CPN DNA was not detected in the blood of any DM patient. CMV DNA was found in the blood of 1 (2.3%) patient. The results do not indicate an increased rate of CMV or CPN infection in patients with type II DM.

Immunological profiles of patients with chronic myeloid leukaemia. I. State before the start of treatment

In view of the increasing interest in the immunotherapy of CML it seems highly desirable to broaden the present knowledge on the immune reactivity of CML patients. A group of 24 patients and 24 healthy controls were studied for the total of 15 immunological parameters, including the prevalence of antibodies against human herpesviruses and papillomaviruses. To clearly discriminate between changes associated with the disease and those induced by the therapy, all patients were enrolled prior to the start of any anti-leukaemic therapy. Statistically significant differences between patients and controls were found in the levels of IgA, C4 component of complement, CRP and IL-6, the production of Th1 cytokines in stimulated CD3 cells and the E. coli stimulatory index. The analysis of the interrelationship between the results obtained in the individual patients presented some unexpected findings, such as the lack of correlation between the CRP and IL-6 levels. It will be the purpose of a follow-up to determine whether and how the immune status of the patients prior to the treatment correlates with their response to therapy and how the individual immunological profiles change in the course of the disease. These observations will be utilized in the future immunotherapeutic studies to constitute the vaccine- and placebo-treated groups.

[Signs of active infection with Chlamydia pneumoniae in patients with coronary heart disease]

BACKGROUND

Possible relationship between Chlamydia pneumoniae (CPN) infection and atherosclerosis has been documented in many seroepidemiological, histological and biological studies. The objectives of the present study were to find out whether serological signs of active CPN infection in patients with coronary heart disease (CHD) are associated with the presence of bacterial DNA in peripheral blood and to correlate with clinical symptoms and to study the dynamics of the markers of CPN infection within a six-month follow-up.

METHODS AND RESULTS

Seventy-one patients with acute CHD were enrolled in the study. They underwent clinical and biochemical tests and were screened for the presence of genus- and type-specific IgG, IgA and IgM antibodies against CPN at admission and then in 3- and 6-month intervals. CPN DNA was detected in peripheral blood using nested PCR. Serological markers of active CPN infection were found in 36 patients (51.4%) while bacterial DNA was detected in two patients only. Laboratory signs of active CPN infection did not correlate with either clinical symptoms or levels of biochemical markers. In most of the patients, titers of anti-CPN antibodies were stable throughout the follow-up. Increase in antibody titers was observed in 23% of patients and was associated with more frequent signs of unstable angina pectoris (p=0.06) but not with higher risk of myocardial infarction within 6 months after the acute episode of CHD.

CONCLUSIONS

In patients with CHD, serological markers of active infection persist for a long time. Nevertheless, their association with the course of CHD or relapse risk was not proved. Bacterial DNA was rarely detected in peripheral blood of the patients. None of the currently available laboratory tests proved adequately effective for detection of ongoing or chronic CPN infection. This project was sponsored by grant IGA MZ CR NI/6811-3 and research plan of Natl. Inst.Publ.Health

Effect of High Glucose Concentrations on Expression of ELAM 1, VCAM-1 and ICAM-1 in HUVEC with and without Cytokine Activation

Diabetes mellitus is associated with an increased prevalence of endothelial dysfunction and development of atherosclerotic vascular diseases. We demonstrate here that hyperglycemia results in the expression of adhesion molecules on endothelial cells in vitro. Incubation of human umbilical vein endothelial cells (HUVEC) in a culture medium with 11.0 mM, 16.5 mM and 22.0 mM glucose concentrations induced the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelial-leukocyte adhesion molecule-1 (ELAM-1). This effect was detectable after 24 h incubation of HUVEC with a high glucose concentration. The effect of high glucose concentration on TNF-alpha induced expression of ELAM-1, VCAM-1 and ICAM-1 was negligible, if at all. These results show that even a short-term exposure of endothelial cells (ECs) to high glucose concentration leads to their activation associated with increased expression of adhesion molecules such as ELAM-1, VCAM-1 and ICAM-1.

Effect of high glucose concentrations on expression of ELAM-1, VCAM-1 and ICAM-1 in HUVEC with and without cytokine activation

Diabetes mellitus is associated with an increased prevalence of endothelial dysfunction and development of atherosclerotic vascular diseases. We demonstrate here that hyperglycemia results in the expression of adhesion molecules on endothelial cells in vitro. Incubation of human umbilical vein endothelial cells (HUVEC) in a culture medium with 11.0 mM, 16.5 mM and 22.0 mM glucose concentrations induced the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelial-leukocyte adhesion molecule-1 (ELAM-1). This effect was detectable after 24 h incubation of HUVEC with a high glucose concentration. The effect of high glucose concentration on TNF-alpha induced expression of ELAM-1, VCAM-1 and ICAM-1 was negligible, if at all. These results show that even a short-term exposure of endothelial cells (ECs) to high glucose concentration leads to their activation associated with increased expression of adhesion molecules such as ELAM-1, VCAM-1 and ICAM-1.

[Infectious and inflammatory factors in the etiology and pathogenesis of atherosclerosis]

Although the metabolic syndrome together with insulin resistance and their consequences are probably basic factors in pathogenesis of atherosclerosis, inflammatory and infectious aspects of this process are unquestionable only in some of the patients. Endothelial dysfunction was identified both in the experiment and in patients after herpes virus simplex 1 infection, cytomegaloviral infection, Chlamydia pneumoniae infection, or Helicobacter pylori infection. However, it is not clear whether it is always caused by direct specific activity of a given pathogen or whether it is a result of inflammatory cytokines activity, heat shock protein activity, or CRP activity. In recent years secondary antibiotic prevention in patients after myocardial infarction has been discussed. Lower mortality rate from acute myocardial infarction and cerebral vascular accidents were found in several observations of patients vaccinated against influenza. In patients with non-stable angina pectoris we have found significantly more frequent occurrence of IgG antibodies against Chlamydia pneumoniae. This occurrence was more frequent in diabetics compared to non-diabetics. Endothelia exposed to cyto-megaloviral infection exprimed adhesive molecules on their surfaces. After an increase of the concentration of glucose in medium to 11.0 mmol/l and 16.5 mmol/l the expression of adhesive molecules after cyto-megaloviral infection increased. Relationship of infection, inflammation, and atherosclerosis has been a subject of intensive investigation in recent years. Discussion of possible consequences of these findings, especially from viewpoint of atherosclerosis prevention and its organ complications, is of the same intensity. Hypothesis about participation of infection and inflammation in pathogenesis of atherosclerosis seems to be very attractive. In spite of the fact that findings supporting this hypothesis cumulate final conclusion can't be made yet.

Interaction of Borrelia burgdorferi sensu lato with Epstein-Barr virus in lymphoblastoid cells

Since the possibility of interruption of latent EBV infection has been suggested by the induction of the lytic virus cycle with chemical substances, other viruses, and by immunosuppression, we hypothesized that the same effect might happen in B. burgdorferi sensu lato infection as happens in Lyme disease patients with positive serology for both agents. We have observed EBV replication in lymphoblastoid cells after superinfection with B. garinii and B. afzelii strains after 1 and 4 h of their interaction. We found that viral and borrelial antigens persisted in the lymphoblasts for 3 and 4 days. Morphological and functional transformation of both agents facilitate their transfer to daughter cells. Association with lymphoblasts and internalization of B. garinii by tube phagocytosis increased replication of viruses more successfully than B. afzelii and chemical inductors. Demonstration of such findings must be interpreted cautiously, but may prove a mixed borrelial and viral cause of severe neurological disease.

Seroprevalence of HHV 8 antibodies among the general population and HIV positive persons in the Czech Republic

BACKGROUND

The seroprevalence rates of herpesvirus 8 (HHV 8) antibodies were determined for the general Czech population and HIV-positive individuals.

OBJECTIVES

Six hundred and sixty six serum samples from the general Czech population and 129 serum samples from HIV-positive persons were tested for the presence of antibodies to the HHV 8 lytic and latent antigens.

STUDY DESIGN

HHV 8 antibodies were detected by the indirect immunofluorescence test.

RESULTS

In the general Czech population, only 2.4 and 0.3% of the serum samples tested positive for antibodies against the lytic and latent HHV 8 antigens, respectively. As many as 34.9 and 10.9% HIV positive individuals had antibodies to the HHV 8 antigens, respectively. Only three of them have developed Kaposi's sarcoma (KS) to date. At the time of KS diagnosis, the three patients had antibodies to both HHV 8 antigens. HIV-positive homo/bisexuals were at significantly higher risk of acquiring HHV 8 infection compared with HIV-positive heterosexuals. The increase in HHV 8 seroprevalence was associated with progression of the HIV infection from stage A to stage B. No correlation was found between the HHV 8 seroprevalence and CD 4+T-lymphocytes counts or the HIV viral load.

CONCLUSIONS

Among the general Czech population, the HHV 8 seroprevalence is as low as in the West European countries. The mean HHV 8 seroprevalence rate in HIV-positive individuals was 34.9% and was comparable with those reported in other low seroprevalence countries.

Serological markers of Chlamydia pneumoniae, cytomegalovirus and Helicobacter pylori infection in diabetic and non-diabetic patients with unstable angina pectoris

The possible role of inflammation in coronary artery disease (CAD) is being recognised, while markers of inflammation (e.g., CRP) and infection with Chlamydia pneumoniae (C. pneumoniae), cytomegalovirus (CMV) and Helicobacter pylori (H. pylori) have been proposed as risk factors for CAD. However, these associations require further evaluation. It is a known fact that diabetic patients suffer from impaired immune response to some pathogens and a high incidence of atherosclerosis. In this case-control study we investigated serological markers of infection with C. pneumoniae, CMV, and H. pylori in a group of 140 patients with unstable angina pectoris (UA), 52 of them having type 2 diabetes mellitus, and in a matched control group. Anamnestic (IgG) and acute infection (IgA) antibodies against the above agents were tested using ELISA or indirect immunofluorescence tests. In patients with UA we found a significantly higher seroprevalence and titres of IgG antibodies against C. pneumoniae (p = 0.04) and increased titres of IgG antibodies against CMV (p = 0.007). No differences were found in IgA antibody response to these pathogens. Antibody response to H. pylori was similar in both groups tested. In diabetic patients with UA, the frequency of group-common IgG antibodies against C. pneumoniae was higher than in the non-diabetic UA patients. The other serological markers studied were comparable in the patients with or without diabetes mellitus. Our findings confirmed association of C. pneumoniae and CMV with cardiovascular heart disease. Moreover, diabetes mellitus may predispose the patients to C. pneumoniae infection. However, serological markers observed do not indicate that destabilisation of angina pectoris is associated with acute C. pneumoniae or CMV infection. No relationship was found between UA and H. pylori infection.

Effect of human cytomegalovirus and glucose on adhesion molecules expression in cultured human endothelial cells

The aim this study was to investigate the effect of glucose on the induction of adhesion molecules by Human cytomegalovirus (HCMV) in endothelial cells in vitro. Primary cultures of human umbilical vein endothelial cells (HUVECs) pretreated with 16.5 mmol/l glucose for 24 hrs were infected with a HCMV strain with tropism for endothelial cells. Expression of adhesion nmolecules (ICAM-1, VCAM-1 and ELAM-1) was measured by flow cytometry. While high concentrations of glucoseperse activated the expression of all three adhesion molecules tested, HCMV induced the expression of ICAM-1 only. Moreover, it potentiated the expression of ICAM-1 in glucose-pretreated HUVECs, while it did not affect at all or slightly suppressed the glucose-activated expression of VCAM-1 and ELAM-1. The modulatory effect of glucose and HCMV on the expression of adhesion molecules in endothelial cells may be applied in increased vulnerability to patients with diabetes mellitus or atherosclerosis.

Presence of herpes simplex virus (HSV) in peripheral leukocytes of patient who developed active HSV infection after bone marrow transplantation

BACKGROUND

Despite of prophylactic antiviral therapy, latent HSV may be reactivated in bone marrow transplant (BMT) recipients and cause serious disease. Rapid diagnosis of HSV infection is needed to prompt institution of appropriate therapy.

OBJECTIVES

We report a case of the allogenic BMT recipient, who developed ulcerative esophagitis which progressed to generalized HSV infection and graft versus host reaction (GVHR).We consider several diagnostic approaches to detection of active HSV infection in this patient.

STUDY DESIGN

Polymerase chain reaction (PCR) was used to detect HSV DNA in esophageal biopsy specimens and peripheral leukocytes (PBL). Isolation of HSV in tissue culture was performed to prove infectious virus in swabs from mucocutaneous lesions or in PBL.

RESULTS

Using PCR, HSV DNA was detected in peripheral leukocytes of the patient who had developed generalized HSV infection accompanied with hepatosplenomegaly and hepatitis. At that time, a fully infectious ACV-resistant HSV was isolated from his PBL. On the other hand, HSV DNA was not detected in PBL of other BMT-recipients with skin- or organ-localized infection.

CONCLUSIONS

Presence of HSV-DNA in PBL of BMT recipients can signalize generalized HSV infection. Isolation of HSV from PBL by cocultivation with human fibroblasts can be used as an alternative diagnostic approach in these patients.

Infection-associated hemophagocytic syndrome complicated by infectious lymphoproliferation: a case report

The case of a 7-year-old boy with virus-associated hemophagocytic syndrome (VAHS) and serologically proven parvovirus B-19 infection is described. The patient with VAHS presented with fever, hepatosplenomegaly, pancytopenia, and hyperlipidemia type IV. After induction therapy with VP-16 and prednisone, partial remission was achieved. Despite maintenance therapy, reinductions, and the addition of cyclosporine A for 3 months, several relapses occurred. The therapy was stopped because of life-threatening complications (Klebsiella sepsis, neutropenic enterocolitis, and stercoral peritonitis). The complications were treated successfully. The patient status was stabilized after splenectomy. However, hepatomegaly progressed slowly and the hyperlipidemia endured. Ten months after the diagnosis leukocytosis with absolute T lymphocytosis appeared. Reactivation of VAHS was suspected and intravenous immunoglobin and then antilymphocyte immunoglobulin ALG therapy were started. The resultant decrease in leukocytosis was prompt, but lymphopenia did not occur. Virostatic treatment with foscarnet was introduced based on human herpesvirus-6 seroconversion. Twenty-six months after the diagnosis, the patient is well, without any sign of VAHS or lymphoproliferation.

Typing of human herpesvirus-6 DNA by restriction endonuclease cleavage of the polymerase chain reaction product

A 591 bp portion of the HindIII H (pZVH14) fragment of human herpesvirus-6 (HHV-6) strains GS (type A) and R-147 (type B) DNA was amplified by the polymerase chain reaction (PCR) using specific primers. While AluI cleaved the amplified DNA of both types of HHV-6, EcoRV cut the type A but not the type B DNA; vice versa, HaeIII cleaved the type B but not the type A DNA.

Antibody against synthetic peptide derived from Epstein-Barr virus-determined nuclear antigen 1 (EBNA-1) in child non-Hodgkin's lymphoma

Antibody reactivity against a synthetic peptide derived from Epstein-Barr virus nuclear antigen 1 (EBNA-1) was determined in 56 cases of child non-Hodgkin's lymphoma and 31 controls. The patients were divided into subgroups based on tumour location and histology and the antibody responses in the various groups were compared. A significant increase in both IgG and IgM antipeptide titres was detected in patients with tumours localized in the abdomen. High IgG titres were also noted in Burkitt-type, lymphoblastic, and centroblastic lymphomas. On the other hand, low or nil IgG titres were found in unclassified malignant lymphomas, in four cases of centroblastic-centrocytic lymphoma and in lymphomas located in the mediastinum. Surprisingly, the occurrence of antipeptide IgM antibody was highest in those tumours, where IgG titres were low, i.e. in subjects with mediastinal tumours and in unclassified malignant lymphomas. However, with the exception of tumours localized in the abdomen and unclassified tumours, the IgM titres in positive individuals were low and comparable with titres found in a part of healthy controls.

Epstein-Barr virus (EBV) antibodies in children with non-Hodgkin's lymphomas

Antibody titres against Epstein-Barr virus (EBV) antigens in children suffering from non-Hodgkin's lymphoma (NHL) were determined. IgG antibody titres against the viral capsid antigen (VCA) and early antigen (EA) exceeded those found in healthy control subjects. On the other hand, antibody titres against EBV-determined nuclear antigen (EBNA complex) were generally lower than in the control group. The most striking phenomenon observed in the patient group was the frequent activation of latent virus infection as revealed by the periodical appearance of anti-EA and IgM class anti-VCA antibodies. Antibody titres against EBV antigens were generally lower among patients with progressing disease than in those with a more favourable course of the illness. The closest relation to EBV based on serological findings, was detected in lymphoblastic lymphomas of Burkitt-type histology, poorly differentiated lymphocytic lymphomas, and in lymphomas localized in the abdomen. The question whether EBV might be involved in a certain proportion of the cases examined is discussed and further approaches to elucidate this problem are suggested.

Antibody response to Epstein-Barr virus antigens in patients with chronic viral infection

We tested antibody titres against Epstein-Barr virus (EBV) antigens in patients suffering from chronic viral disease and compared them with those determined in sex- and age-matched healthy controls. Patient sera showed signs of active EBV infection [antibodies against early antigen (EA) and/or viral capsid antigen (VCA) in the IgM or IgA classes] significantly more frequently than the control group. Correspondingly, geometric mean titres (GMT) of antibodies against all viral antigens were elevated in the patients. The strongest association with EBV was observed in patients whose clinical symptoms closely resembled infectious mononucleosis: 92% of the subjects in this subgroup possessed anti-EA and 41 and 25% had IgM and IgA anti-VCA antibody, respectively. In patients with signs of lymphoproliferation only and in those suffering from frequent respiratory infections the association with EBV was less marked but still significant. Patients with transient defects in humoral and cellular immunity mounted higher titres against VCA in the IgG class than those without immune defects.

Chemically purified serum factor can induce both Epstein-Barr virus antigen synthesis and cell differentiation

The effects of purified Epstein-Barr virus-inducing serum factor (EIF) on the lymphoblastoid cell line Raji latently infected with Epstein-Barr virus were studied. Activated serum factor was capable of both: cooperating with n-butyrate and/or TPA in inducing synthesis of EBV antigens and triggering cell differentiation towards plasma cell as determined by electron microscopy. It seems therefore that the same serum component was involved in the induction of both phenomena.

Effect of n-butyrate on superinfection of Raji lymphoblastoid cell line by Epstein-Barr virus

The effect of n-butyrate on superinfectability of virus-nonproducer Raji cells by the P3HR-1 strain of Epstein-Barr virus (EBV) was investigated. n-Butyrate is known to be a potent inducer of virus antigen synthesis in virus-producer cell lines and of cell differentiation in virus nonproducers. The drug inhibited the growth of Raji cells but did not interfere markedly with cell viability. It induced a low rate of early antigen (EA) synthesis in about 1-2% of noninfected Raji cells. While the number of superinfectable cells remained relatively constant after treatment with butyrate, an increase in antigen positivity was noted in untreated cells. This relative decrease in sensitivity to superinfection in butyrate-treated Raji cells was more pronounced in cultures that had been treated with the drug for 48 or 72 hr as compared to those treated for 24 hr. A blocking of the treated cells in the certain cell-cycle phase and their drug-induced differentiation towards plasma cells might have been involved in the phenomenon described.

Effect of n-butyrate on transformation of human lymphocytes by Epstein-Barr virus

3 mM n-butyrate, which effectively induces synthesis of Epstein-Barr virus (EBV) antigens in the producer P3HR-1 cell line, inhibited the transformation of umbilical cord blood lymphocytes by EBV. The drug inhibited both EBNA synthesis and stimulation of host cell DNA synthesis by strain B95-8. This effect was less pronounced at lower concentrations, but even at 0.1 mM (which did not affect DNA synthesis in EBNA and stimulation of host cell DNA synthesis in EBV-infected lymphocytes were delayed.