PR8 influenza virus infection impairs serum thymic activity levels and thymus-derived immune functions in mice.

The levels of serum thymic activity (STA), the Thy-1.2 positivity of spleen "spontaneous" rosette-forming cells (SSRFCs) (measured in terms of Az sensitivity), as well as the blastogenic response to specific mitogens for T-lymphocytes, were studied in Balb/C mice after intranasal infection with A/PR/8/34 (HON1) influenza virus. As early as 12 hours, and more drastically, 24 hours the levels of STA were profoundly decreased after virus infection. Spleen Az sensitivity and blastogenic response of thymocytes and splenocytes to stimulation with Concanavalin A and Phytohemagglutinin, respectively, were depressed only later (day 2 or 3). These changes remain evident for about 1 week and later revert to normal values. All of the effects described are dose-dependent and appear to be virus related. Thence the PR8 virus infection initially induces a decrease of STA levels and secondly a impairment of thymus-derived immune functions.

Role of hemolytic factors of Sendai virus on human erythrocyte membrane fluidity.

In order to establish whether the hemolytic activity of Sendai virus might be related to changes of the membrane fluidity of sensitive cells, membrane fluidity variations have been recorded in human erythrocytes ghosts in the presence of Sendai and PR 8 viral particles. A decrease of membrane fluidity is elicited by Sendai and Pr 8 virions and by non hemolytic Sendai virus after trypsinization; the effect on membrane fluidity of sendai virus is strongly reduced after pyridine treatment which abolishes hemolytic action.

Interaction of Sendai virus with human erythrocytes. IV - Hemolytic factors.

A study on the composition of structural proteins of Sendai virus deprived of hemolytic activity by pyridine and trypsin in controlled condition was carried out. Pyridine leaves unaffected the electrophoresis pattern of virus proteins; in virus treated with trypsin a drastic reduction of F protein was observed. Researches reported indicate that two factors are required for hemolytic activity of Sendai virus the F protein and the phospholipids of the outer layer of envelope.

[Plant antigens with immunological properties. II. Further studies of the chemical characteristics and immunological properties of a grass pollen extract]. / Antigeni vegetali dotati di proprietà immunologiche. II. Ulteriori richerche sulle caratteristiche chimiche e sulle proprietà immunologiche di un estratto di pollini di graminacee

This second study carried out on an extract of two grass pollens (Poa pratensis and Phleum pratense) demonstrated the presence of N-acetilglucosamine and sialic acid in the extract (RFEX). Moreover the extract has confirmed its characteristics biologic activity i.e. the inhibition of the phenomenon of immune hemolysis with a different technique too, even having the antibodies of the treated animals the complement fixing activity. No appreciable changes of the immunoelectrophoresis pattern in the serum of the immunized mice have been noticed.