Tumoral infiltrate after local treatment with interferon in squamous cell carcinoma

Using monoclonal antibodies UCHL-1 (T lymphocytes), MT-1 (pan T) and L-26 (B lymphocytes) in the study of the tumoral infiltrate after local treatment with alpha interferon (Roferon) in patients with squamous cell carcinoma of the lower lip, it was observed that: the proportion of UCHL-1 positive cells was between 30% and 80%, the proportion of MT-1 positive cells was of 85% and that of the L-26 positive cells was of 30% of all the cells in the infiltrate. In the area in which after treatment with interferon the tumoral structures had disappeared, the proportion of T lymphocytes was smaller than in the areas in which the tumoral structures were still present. The therapeutic effect of interferon is due both to the direct effects on the tumoral cell and also to the indirect effects, namely the activation of the cytotoxic T lymphocytes and of other cells in the tumoral infiltrate.

Interleukin-2 (IL-2) in the treatment of malignant brain tumors (glioblastomas)

The present study is aimed to provide a new possible approach to the treatment of glioblastomas, in an effort to control the extremely severe evolution of these tumors. Thus, from May 28, 1991, we started the administration of IL-2 (produced at the "Victor Babeş" Institute, Bucharest) in 9 glioblastoma patients (operated on at the Neurosurgery department VII of the "G. Marinescu" Hospital, Bucharest) by repeated intraoperative and postoperative local injections. The survival period from the first IL-2 administration was 7 months (1 case), 8 months (2 cases), 11 months (2 cases), 14 months (1 case) and 17 months (1 case). There are only 2 survivors: one 4 months and the other 23 months following the first injection of IL-2. The survivor whose condition 23 months following introduction of IL-2 therapy is very good, demonstrates that IL-2 offers some chance to these hopeless patients.

Highly active effect of alpha interferon in blocking the cutaneous delayed hypersensitivity

A group of 13 patients with contact dermatitis to various chemical compounds such as potassium dichromate, nickel sulphate, formaldehyde and balsam of Peru, was investigated by patch test and by the agreement between the history of disease and the patch test, the specific allergen involved in each special case could be demonstrated. Two-three days after the first patch test three normal skin areas were chosen. The first area was intradermally infiltrated with alpha-2a Interferon (IFN) (100,000 I.U. in 1 ml), the second area was infiltrated with saline and the third area, considered as control, did not receive any treatment. Once more the corresponding allergen was applied into the skin in a second patch-test. After 48 hours in the IFN infiltrated area, only the delayed contact hypersensitivity become negative thus proving that alpha-2a IFN behaves as an efficient inhibitor of these immune effector reactions. Since the lymphocytes involved in the delayed type hypersensitivity reactions (in our case contact dermatitis) belong to the T helper line, i.e., are CD-4 positive cells we conclude that alpha-2a IFN in vivo is an efficient inhibitor of the activation of these cells. This effect achieved by any CD-4(+) DTH clones does not depend on their antigenic specificity. Some clinical trials are now in progress in our laboratory to turn to account this important biological effect in the clinical practice as an efficient inhibitor in skin contact dermatitis.

Therapeutic effect of intralesional interferon (Roferon) in squamous cell carcinoma

Recombinant alpha-2 interferon (IFN)--Roferon--100,000 IU/ml was intralesionally administered in 8 cases of squamous cell carcinoma (SCC) three times a week during 4-6 weeks in inoculations of 1 ml each. The therapeutic effect was scored as major--more than 60% reduction of the tumor size, moderate--30-60% reduction of the tumor mass and, nonreactive--less than 30% reduction of the tumor size. Three cases showed a major reduction, three showed a moderate reduction and two patients showed no reduction of the tumor volume. Histopathological examination of the surgically removed tumors after completion of the Roferon administration confirmed the clinical diagnosis of squamous cell carcinoma and revealed that an intense leukocyte, mainly lymphocytes, infiltration can be observed along with necrotic centers, progressively surrounding and reducing in size the tumor islets, thus proving an intense activation of the immune effector reactions against tumor cells.

Intralesional human leukocyte interferon treatment alone or associated with IL-2 in non-AIDS related Kaposi's sarcoma

Patients with classical European Kaposi's sarcoma were treated by intra- and peritumoral injections of human alpha leukocyte interferon (IFN) (12 cases) or, alternatively, with IFN and naturally synthesized IL-2 (8 cases). All the patients were HIV negative with tumors which had been present for at least six months. In each patient, one tumor received 1 ml (50,000 IU) IFN alone or alternatively associated with 1 ml IL-2 twice a week for 4-6 weeks; another nodule situated 10-12 cm away was considered as a control and remained uninjected. The clinical follow-up revealed that, in the same patient in the same anatomical area, the treated nodule was cured in all the investigated cases; the untreated one was not. These data strongly suggest that IFN is the factor responsible for the involution and final cure of these Kaposi tumors treated by perilesional inoculations. Association with IL-2 (and certainly also other interleukins) increases the beneficial clinical activation of the tumor involution. Histological examination showed that important histopathological changes occur in the treated nodules: complete disappearance of the Kaposi's aspect, fibrosclerous modifications progressively replacing the fibroblasts characteristic of Kaposi's sarcoma, abundant infiltrations of leukocytes, especially lymphocytes and necrotic patches, often with hemorrhagic centers. IL-2 association seems to especially induce this last type of histological phenomenon.

Human leukocyte interferon treatment associated with IL-2 in the non-AIDS related Kaposi's sarcoma

Patients with classical European Kaposi's sarcoma have been treated by intra- and peritumoral injections of human alpha-leukocyte interferon (IFN) (12 cases) or alternatively with IFN and naturally synthetized IL-2 (8 cases). All the patients were HIV negative their tumour appearing at least six months before. In each patient one tumour received 1 ml (50,000 IU) IFM alone or associated, alternatively with 1 ml IL-2, twice a week during 4-6 weeks, whereas another nodule situated 8-10 cm apart was considered as control and remained uninjected. The clinical follow-up revealed that in the same patient in the same anatomical area the treated nodule was cured in all the investigated cases while the untreated nodule was not. These data undoubtedly prove that IFN is the responsible factor for the involution and final cure of the Kaposi tumours treated by perilesional inoculations. Association with IL-2 (and certainly also other interleukins) increases the beneficial clinical effect activating the tumour involution. The histological examination showed that important histopathological changes occur in the treated nodules, i.e., complete disappearance of the Kaposi's aspect; fibrosclerous modifications progressively replacing the abundant fibroblastic cells characteristic of Kaposi's tumour; abundant infiltrations of leukocytes especially lymphocytes; necrotic patches often appearing along with hemorrhagic centers. IL-2 association seems to frequently induce especially this last type of histological phenomena.

Correlation of serum interferon with some clinical and humoral signs of systemic lupus erythematosus

The serum level of total interferon (IFN) was measured in 15 male patients with systemic lupus erythematosus (SLE) in the active phase and in remission, before and during corticotherapy. The values found were correlated with the clinical and humoral signs of disease. The IFN titer was high in the active phase of disease and was correlated with fever, extension of skin rash, polyarthritis, myositis, autoimmune hemolysis, cardiac and cerebral involvement as well as with ESR, reacting protein C, CIC, ANF and the percentage of LE cells. Isolated LE nephropathy without rapidly progressive or advanced renal failure was not associated with high IFN titer.

The role of tumor angiogenesis factor (TAF) in the tumor growth. Pathological aspects

This work was carried out on control and immunosuppressed A2G mice inoculated with murine tumour cells (Ehrlich ascites) and human ones (KB cell line). The growth of the tumours was conditioned by the growth of the fibrovascular stromas as a response of the host organism to the TAF secretion. This process is a nonimmunological response, the differences between control and immunosuppressed mice being of no statistical significance.

S-phase detailed analysis in KB cells by bromdeoxyuridine labelling

A method based on the sequential BrdU incorporation followed by differential spiralization of the chromosomes was used for analysis of S-phase in KB cells when Brdu was added to the cultures for 19, 24 and 26 hours before fixation. The S-phase was subdivided into three subphases, each recognisable by a specific incorporation pattern at metaphase: late-S (LS), middle-S (MS) and early -S (ES). Two other intermediary subphases, mid-early S (mES) and mid-late S (mLS) have also been distinguished but their accurate identification is generally difficult. A high degree of asynchrony in KB cells population was observed as well as a wide variability concerning the duration of S-phase (BrdU = bromdeoxyuridine).

The effect of human alpha leukocyte interferon (IFN) on the frequency of sister chromatid exchanges (SCE) in the KB cell line

Concentrations of 50, 500 and 5,000 iu/ml of natural human alpha leukocyte interferon (IFN) were added into the culture medium of KB cells, 4 h after serial passage, in the presence of 5-bromo-desoxyuridine (Brdu) at 10 micrograms/ml. Similar cultures without IFN were set up as controls. After 72 h of incubation, the harlequin technique (differential staining of sister chromatids) was applied in order to discriminate among the metaphases of different generations and to appreciate the frequency of sister chromatid exchanges (SCE) in the second generation cells. The incidence of sister chromatid exchanges was slightly increased following IFN treatment but no dose-effect relationships were observed. At the same time, cell cycle kinetics estimated as replication index (RI) and average generation time (AGT) was not modified in IFN-treated cells as against the controls.

Intralesional human leukocyte interferon treatment in the non-AIDS related Kaposi's sarcoma

Twelve patients with classical European Kaposi's sarcoma have been treated by intra- and peritumoral injections of human alpha leukocyte interferon (IFN)--Ginterferon ("V. Babeş Institute", Bucharest). All the patients were HIV negative their tumour appearing at least six months before. In each patient one tumour received 1 ml (50,000 IU) IFN twice a week during 6-7 weeks whereas another nodule considered as control remained uninjected. After treatment biopsies of both the IFN-treated and the untreated nodules were performed in 8 patients and histological examinations were carried out. The clinical follow-up revealed: The skin colour progressively changed from purple red to dark reddish or even brown in all the IFN-treated tumours and only in 3 of the untreated ones (p less than 0.001). The consistency of the nodules decreased in all the treated tumours and only in 2 of the untreated ones (p less than 0.001). The tumour thickness decreased in 9 of the treated tumours and in none of the untreated ones (p less than 0.001). The surface of the lesions decreased in 4 of the treated nodules but not in the untreated ones (p less than 0.05). The IFN-inoculated tumours were gradually cured even in the four cases in which during the treatment some other tumour progressed or even new lesions appeared. The histological examination showed that: all the IFN-treated tumours were either predominantly sarcomatous or predominantly angiomatous. The typical Kaposi aspect disappeared totally in 2 of the cases examined, and in 3 a fibrosclerotic massive change was obvious.(ABSTRACT TRUNCATED AT 250 WORDS)

Interferon efficiency in the treatment of herpetic dermatites. II. Comparison between human leukocyte interferon (Ginterferon) and a recombinant interferon (Roferon)

The comparative efficiency of a recombinant interferon-Roferon (R-IFN) and a human, naturally synthetized interferon-Ginterferon (G-IFN), applied as ointments in the treatment of herpetic dermatites, was studied in a blind trial. It was found that R-IFN in doses of 20,000 IU/g has practically similar results as G-IFN in doses of 10,000 IU/g therefore half the dose of the former product. Thus both preparations reduced significantly the mean duration of a herpetic dermatitis attack and both proved more efficient on smaller lesions (less than 2 sq.cm) than on larger ones (over 2 sq.cm). Likewise with both preparations the reduction of the healing period was more marked when administered in the first 2-3 days after onset. It was also found that the arrest of new vesicle appearance after two days of treatment is a reliable clinical criterion for the estimation of IFN capacity to block effectively viral multiplication in the host's epithelial cells. Finally the efficacy of both R-IFN and G-IFN proved similar whatever the localization of disease (oral or genital) or in their capacity to prevent relapses or the appearance of bacterial complications.

An experimental model comparing the antineoplastic and the immunosuppressive effects of some cytostatics

An experimental model evaluating comparatively the antineoplastic and the immunosuppressive effects of some cytostatics (cyclophosphamide and vinblastine) is described in the present paper. Different cytostatic doses were intraperitoneally administered in mice which were 24 hours later grafted with a suspension of human tumoral KB cells. The xenograft acceptance was macroscopically and microscopically recorded 21 days later. By the Reed and Muench method and also by graphical extrapolation the LD50 (lethal dose for 50% animals) and the TD50 (the immunosuppressive dose enabling 50% animals to accept the xenografts) could thus be determined for both cyclophosphamide and vinblastine. The number (percent) of the tumour bearing animals three weeks after grafting was considered as an indicator of the cytostatic dose at which the immunosuppressive effect exceeded the antineoplastic effect. The in vitro effect of the same drugs on the KB cells was tested by inoculating different cytostatic doses in the cell cultures and counting at different time intervals the adherent as well as the nonadherent cells. The in vitro drug toxicity on the KB cell cultures was also determined by the trypan blue exclusion test. Both cyclophosphamide and vinblastine proved to be in vitro highly potent cytostatics i.e. when directly acting on the KB cells. This effect was dose correlated for both the considered drugs. However our in vivo experiments have shown that none of the observed effects when considering the direct action of the cytostatic on the cultured cells could not safely be extrapolated in vivo. Our results have an obvious practical importance when considering the therapeutical approaches in the neoplastic diseases. They demonstrate that the increase in cytostatic dose is not directly correlated to the antineoplastic effect since it reaches a limit at which the immunosuppressive effect highly exceed the tumour growth inhibition effect. The described experimental model could also be used in comparative estimations of the biological effects of different cytostatic drugs possibly referred to a standard immunosuppressive reagent as an antilymphocyte antiserum.

Diagnostic value of serum interferon level in systemic lupus erythematosus

In all the patients with systemic lupus erythematosus (SLE) tested in the active phase of the disease the serum interferon (IFN) level increases above the normal value (20 I.U./ml) reaching in some cases 80-160 I.U./ml. The detection of this increased level of IFN is useful to discriminate if some diseases such as glomerulonephritis or hemolytic anemias develop as part of a systemic auto-immune disorder since in such pathologic conditions lacking auto-immune mechanisms the serum IFN level is not increased. The detection of the serum IFN level proved to be a useful test in the follow-up of the clinical evolution as well as for the efficiency of the immunosuppressive therapy since in all the investigated cases IFN level decreased to normal after Cortisone administration concomitantly with the clinical remission of the disease. The above described data support the assumption that in the pathogeny of auto-immune diseases, SLE in our case, there are some initial cell-mediated auto-immune phenomena such as cell-mediated auto-cytotoxicity leading to a massive activation of the CTL and NK cells and consequently to the over-production of some lymphokines such as IFN.

Anti-phospholipase C antibodies inhibit the lectin-induced proliferation of human lymphocytes

A novel approach was used to assess the role of phosphoinositide hydrolysis in the mitogenic action of phytohemagglutinin (PHA) or concanavalin A (ConA). The treatment of human peripheral blood leukocytes (PBL) with monospecific antibodies against phospholipase C (PLC) produced a dose-dependent inhibition (up to 100%) of PHA (10 micrograms/ml) or ConA (25 micrograms/ml) proliferative effects. Thus, the activation of membrane-bound PLC is a sine-qua-non condition for lectin-induced proliferation of T lymphocytes. The key-role of PLC versus protein kinase C (PKC) is stressed by the fact that the inhibition of PKC with Hidaka's compound H-7 (40 microM) produced only a partial blockade (about 25%) of lectin mitogenic effect.

Interferon level in human normal sera

Interferon (IFN) level in the sera of normal humans was determined by their protective effect on a KB cell culture against the cytopathic effect (CPE) induced by vesicular stomatitis virus. The technique revealed all the three known types of IFN. In the investigated population 15 of 37 sera (40%) were found to protect against the CPE at 1/10 dilution, 11 of 37 (30%) still protect at 1/20 dilution, and 7 of 37 sera (19%) still protect at a dilution of 1/40. No serum was found to have detectable IFN levels at 1/80 dilution. We can thus consider that the normal serum level ranges up to a 1/20 dilution i.e., up to 20 IU/ml. The above titers are slightly higher than the normal IFN level reported by other investigators in other human populations, although no clear reasons can be given to account for the differences.

The use of differential staining of sister chromatid to estimate the in vitro effect of human alpha interferon on cell division in normal and tumour cells

Concentration of 10, 100 and 1000 I.U./ml of human leukocyte alpha interferon (IFN) were added into peripheral human blood (PBL) cultures and in KB cell cultures in the presence of 5-bromdeoxyuridine (BrdU) at 10 micrograms/ml. After 72 hours the differential staining of sister chromatid (harlequin) technique was applied in order to differentiate among the metaphases of successive cell generations occurring in the presence of IFN. The frequency of the first (M1), second (M2) and third (M3) metaphases was recorded and the replication index (RI) as well as the average generation time (AGT) was calculated for untreated controls and for each of the IFN concentrations used, both in the blood cultures and in the KB cells. In the PBL cultures a clear dose-related inhibitory effect of IFN on cell division was observed, the RI values being lessened whereas the AGT concomitantly increased by increasing the IFN concentrations. An increase in M1 metaphase frequency was observed concomitantly with a diminished number of M3 cells. In KB cells the division kinetics was not influenced by IFN as indicated by similar RI and AGT values observed in controls and in IFN treated cells. However, the frequencies of both M1 and M3 cells were slightly diminished concomitantly with a discrete augmentation of M2 cell number. The differential staining of sister chromatid thus proved a highly useful technique to investigate the different sensitivity of the normal and malignant cells to the growth inhibitory effect induced by alpha IFN in vitro.

Ginterferon (human leukocyte interferon) efficiency in the treatment of viral diseases. 1. Efficiency in viral keratoconjunctivitis

Ginterferon is a human leukocyte interferon (IFN) produced in the "V. Babes" Institute by in vitro culture of leukocytes separated from neonatal cord blood. Ginterferon (50,000 IU/ml) was administered to 40 patients who suffered for at least two weeks of a hepatic keratoconjunctivitis resistant to treatment with conventional regimens of human immunoglobulins, Iduviran or topical antiinflammatory drugs. In 35 cases (87%) complete recovery (total epithelialization and disappearance of all symptoms) occurred in a significantly shorter time (10-14 days) as compared to similar cases which recovered after 30-40 days by conventional treatment. Local or general untoward effects were not observed in any of the patients. Recovery in the remaining 5 cases was slower, 28-30 days. This slow response may have been due to unusual weakness of the general immunobiological condition in these patients (myocardial infarction or repeated stress) which might have favoured repeated waves of virus spreads from foci of viral latency which are not attained by the topically administered IFN.

Study of cell surface antigens induced by herpes simplex virus. Note I. Identification of the antigens by means of protein A-containing staphylococci

A rapid, easy-to-perform and specific technique for the visualization of herpes simplex virus (HSV)-induced cell surface antigens is described. The technique consists in the incubation of HSV-infected cells with hyperimmune HSV antiserum and formation of rosettes with FITC-labelled Cowan strain staphylococci containing protein A. The "nonspecific background" of the reaction can be estimated by comparison with the rate of bacteria binding by control cells not incubated with HSV antiserum.

Study of host antigens in the envelopes of different myxo- and paramyxoviruses cultivated in the embryonated hen egg

By immunoelectrophoretic analysis it was shown that different viruses--such as myxo- (influenza A0PR8) and paramyxoviruses (Sendai, SV5, NDV, mumps)--cultivated in the same host cells (chorioallantoic membranes) incorporate similar host antigens into their envelopes. The amount of host cell antigens incorporated into the virus envelopes differs from one virus to another. The fact that incorporation of host cell antigens occurs only after a virus-induced modification seems to be a general characteristic of enveloped viruses such as myxo- and paramyxoviruses.

Immunoelectrophoretic study on the host antigens of Sendai virus cultivated in different substrates (embryonated hen eggs and KB cells). Note II. Analysis of KB cell host antigens

It could be demonstrated by immunoelectrophoretic analysis that the host antigen incorporated in the envelopes of Sendai virus cultivated in KB cells (Sendai/KB) is characteristic of these cells and does not occur in the envelopes of the same virus grown in the embryonated hen egg (Sendai/egg). This host antigen appears from the first passage in KB cells and is constantly maintained over subsequent passages. The glycoproteins released by Triton X-100 disruption from Sendai/KB envelopes have a concomitant antigenic specificity for both virus and host. In the case of Sendai/egg virus, exclusively virus-specific macromolecules are also released.

Immunoelectrophoretic study of the host antigens of Sendai virus cultivated in different substrates (embryonated hen eggs and KB cells). Note I. Analysis of chorioallantoic membrane host antigens

The immunoelectrophhoretic analysis of two preparations of the same virus cultivated in different substrates (Sendai/egg and Sendai/KB) demonstrate that virus envelopes contain: a) identical virus-specific antigens (but also some virus antigens with only partial immunochemical identity, or even non-identity); b) antigens incorporated by the virus from the host cell, during assembly and release. The latter differ according to the host, and some of them are only partially identical with the corresponding antigens of the host cell, which suggests that host cell glycoproteins are incorporated into the virus envelope after certain virus-induced modifications.

Immunoelectrophoretic study of Sendae virus envelope antigens with hyperimmune sera prepared in different laboratory animals

At similar HAI titers rabbit sera reveal a larger number of fractions (ten) in immunoelectrophoretic analysis of Sendai virus envelopes than do guinea pig sera, which only yield three distinct fractions. These differences are observed in both rocket and crossed immunoelectrophoresis, and are more marked in the latter. The number of fractions revealed does not differ in relation to the antigen used for hyperimmunization (intact Sendai virus, Triton-disrupted virus or envelope fractions extracted by Triton or Tween-ether). Solubilized Sendai virus envelopes obtained by Tween-ether or Triton treatment contain host antigens in their structure, the same as intact virus.

Significance of some immunochemical data for the viral pathogeny of multiple sclerosis

Cerebrospinal fluid (CSF) samples from 124 patients with different neurological diseases (35 having an ascertained diagnosis of multiple sclerosis (MS) and 20--of subacute sclerosing panencephalitis (SSPE)) were investigated by immunoelectrophoresis. The correlation between the "secretory" immunoelectrophoretic pattern of CSF proteins in MS and SSPE patients and the incidence of antimeasles HI antibodies in the CSF is analysed. The results point to a different pathogenic significance of the presence of antimeasles antibodies : a) persistent measles virus infection in SSPE and b) a particular genetic constitution, coincident with a hyperreactivity to measles virus, in MS.

An antigen for the diagnosis of M. pneumoniae infections by passive hemagglutination

The authors establish the optimal conditions (protein concentration, temperature) for the coupling of purified mycoplasma antigen to sheep red blood cells, in order to obtain an antigenic complex stable for at least 1 year. This comples allows specific determination by passive hemagglutination--a simple and rapid technique--of anti-mycoplasma antibodies in the sera of men or animals suspected of mycoplasma infections. Under the stated experimental conditions, antibody titers equal to or higher than 1/128 indicate an infection with M. pneumoniae.

Immunoelectrophoretic investigations on Sendai virus envelope antigens in relation to host antigens

The different antigenic fractions characteristic of egg-cultivated Sendai virus envelopes were studied by immunoelectrophoresis. Virus-specific and host-specific fractions were identified. It was proved that incorporation of the host membrane fragments into the viral envelopes is not a passive phenomenon. During the last stages of its assembly and release, the virus incorporates into the envelopes some host glycoproteins, after an active biochemical processing resulting in a considerable reduction of their molecular weight, while the host antigenic determinants remain almost unaltered.

Passive hemagglutination and complement fixation reactions in the early diagnosis of Mycoplasma pneumoniae infections

Complement fixation (CF) and passive hemagglutination (PHA) tests (the latter with a M. pneumoniae antigen coupled by glutaraldehyde onto red blood cells) were performed in 263 patients with various infectious diseases (mostly in the 1st and 2nd week after onset) and non-infectious ones. CF reaction proved to be inappropriate for the early etiological diagnosis of mycoplasma infections, since the high titers were distributed undifferentially among the various patient groups and many sera (38%) showed anticomplementary activity. A PHA titer of at least 1/128 (preferably of 1/512) points to the presence of a M. pneumoniae infection, especially if clinical, radiological and laboratory data suggest a nonbacterial or mixed pneumonia. The diagnosis is often early enough to orientate the etiological therapy towards macrolides and tetracyclines. The PHA reaction recommended is specific, sensitive, reproducible and easy to perform.

Immunoelectrophoretic characterization of Sendai virus antigens

Antigens extracted from Sendai virus by solubilization with Triton X-100 (Tx). Tween-20 (Tw) or Triton X-100 and SDS (Tx-SDS) were analysed by rocket, crossed and tandem immunoelectrophoresis. The migration of these antigens through 1% agarose supplemented with guinea pig anti-viral envelope protein anti-serum shows that Tx and Tw antigens consist of three fractions differing in their quantitative ratios, while Tx-SDS exhibits five different fractions. The method proved to be useful for the identification of anti-host antibodies in immune antisera by means of an antigen extracted from the chorio-allantoic membrane of embryonated hen eggs.

Further immunological evidence for the presence of Fc receptors on the surface of HSV-infected cells

By coupling passive hemadsorption (PHads) reaction with a complement-mediated cytotoxicity test (CT) it is possible to detect the presence on the surface of hamster embryo fibroblasts of Forssman antigens, hindering the demonstration by PHads of the receptors for the Fc-fragment of immunoglobulins (FcR), possibly induced by herpes simplex virus (HSV). These antigens are acetone- and formol-resistant, but they are destroyed by treatment with methanol or ethanol. However, CT with anti-sheep RBC serum performed in HSV-infected monkey kidney cells is always negative, which proves that the attachment of immunoglobulins to these cells occurs exclusively through their Fc-fragments.

Preliminary investigations on the diagnostic value of passive hemagglutination and complement fixation tests in infections with Mycoplasma pneumoniae

In order to evaluate the efficiency of passive hemagglutination (PHA) and complement fixation (CF) tests for the diagnosis of M. pneumoniae infections, 144 serum samples--out of which 81 from patients with respiratory and cutaneous infections and 63 from subjects with other diseases (controls)--were comparatively investigated by the two methods. The PHA test made evident a positivity index of 65% in the case of mixed pneumonias, as against 17% in controls, while the results obtained by CF were almost identical in the two groups investigated. The high specificity and sensitivity of the PHA reaction recommend this method for the diagnosis of acute M. pneumoniae infections.

Changes in the macromolecular structure of DNA-RNA-protein complexes induced by gel-filtration on sephadex G-25

Hydrodynamic shearing forces appearing during nucleoprotein gel-filtration on Sephadex G-25 cause a disruption of the macromolecular structure in nucleoproleins.

The effect of these shearing forces can be observed both in electron micrographs and by electro­phoretic analysis.

The decrease of the molecular weight and also the changes in the electronegative charge,mole­cular weight ratio cause an increase of the electrophoretic mobility of the gel-filtered highly poly­merized DNA and of the RNA complexed to it compared with the not gel-filtered nucleoprotein.