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TR/Patoc slide test, ELISA and TIA (Thin-Layer Immunoassay) were evaluated for their use in a rapid serodiagnosis of human leptospirosis. The results obtained indicated that the TR/Patoc slide test is very sensitive and able to detect within a few minutes early antibodies against whichever serovar of leptospires, like the antigens of the Galton test. The value of the ELISA test in detecting antibodies at a low level is confirmed. The TIA assay, employed here for the first time for the diagnosis of leptospirosis, though sensitive seemed too long to perform and consequently it is not a test of choice for a rapid screening of sera.

The antigenemia and the patterns of antibodies to core protein (p24) and envelope glycoproteins (gp41, gp120) have been investigated in 81 patients with Human Immunodeficiency Virus (HIV) infection followed prospectively for 24 months. HIV antigen was detectable in 23 (28.4%) patients at entry to the study (13/13 with AIDS and 10/23 with ARC) and in 33 (40.7%) at the end (25/28 with AIDS, 5/12 with ARC e 3/14 with LAS). Anti-p24 were positive in 51 (63.0%) patients at the entry (26/30 symptomless, 13/15 with LAS e 12/23 with ARC) and in 41 (50.6%) at the end of the study (23/27 symptomless, 9/14 with LAS, 7/12 with ARC e 2/28 with AIDS). All patients were positive for anti-gp41 and showed no significant changes in the antibody titers during the two years of follow-up; by contrast, anti-gp120 was undetectable in most patients (26/28) with AIDS. Clinical progression in a high proportion of patients was associated with the appearance of HIV antigen, with the decline of anti-p24 titers and with no antibody reactivity to gp120 glycoprotein.

A Dot Immunobinding (DIB) assay has been applied to the serodiagnosis of human hydatidosis and its results have been compared with those obtained with the enzyme-linked immunosorbent assay (ELISA). The two techniques have been shown to be closely related (p greater than 0.001), highly sensitive (92.0% of positive results in 75 sera from patients with hepatic or pulmonary hydatidosis) and specific (93.5% of negative results in 31 sera from patients affected by other parasitic diseases and 100% of negative results in 30 normal controls). DIB however is more economical and takes less time (only 4 hours) than ELISA. DIB could be an useful tool in field epidemiological surveys since it is sensitive, specific, simple to perform and it does not require any expensive apparatus.

Radial counter-immunoelectrophoresis was evaluated with sera from surgically-confirmed hydatidosis cases, patients with other parasitic diseases and healthy controls. Radial counter-immunoelectrophoresis was a sensitive as classic counter-immunoelectrophoresis based on the same positivity criterion and was equally specific for the immunodiagnosis of human hydatidosis. The procedure appears to be simple and rapid (the immunoprecipitation step requires just 5 minutes) and merits consideration.

A recently developed immunoenzymatic technique, the Dot Immunobinding assay (DIB), has been applied to the rapid detection of staphylococcal enterotoxin B in filtered culture supernatants. The test has been shown to be highly sensitive and specific, easy to perform and rapid (only 4 hours). The use of nitrocellulose paper as the solid phase allows the exact standardization of the amount of antigen employed and it avoids the overnight incubation usually necessary with the conventional enzyme-linked immunosorbent assay (ELISA).

Humoral and cellular immune responses to Salmonella typhi have been studied in nine children with typhoid fever. By using dot immunobinding assay, anti-O-polysaccharide chain and antilipid A antibody titers have been evaluated during the course of the disease. Anti-O-polysaccharide chain antibody titers are lower at the first week and increase up to the third week of the infection. On the other hand, antilipid A antibody levels, which are already higher at the beginning of the disease, progressively augment during the following weeks. Concerning cellular immunity to S. typhi, antibacterial activity mediated by typhoid peripheral mononuclear cells has been determined. Results show this function to be depressed in the initial phase of typhoid, increasing with the time. Together, these data bring new insight on immunity in typhoid patients.

An ELIEDA test for hydatidosis was evaluated with sera from preoperative, surgically-confirmed hydatidosis cases, postoperative hydatidosis patients, persons with other parasitic disease and healthy donors. ELIEDA was more sensitive than the counter-immunoelectrophoresis test based on the same positivity criterion and was equally specific for the immunodiagnosis of human hydatidosis. The procedure appears to be simple and rapid and merits consideration in that it determines specific classes of antibodies involved in the immune response which appear to be useful in following the evolution of hydatid cysts.

In some of the sera from patients with amoebiasis circulating immune complexes are present which are thought to interact with lymphoid cells, enabling them to elicit a burst of oxygen consumption in PMNs. The intensity of chemiluminescence is related to the presence of C3+ and Fc IgG+ cells in the lymphoid cell suspensions employed. The generation and release of highly reactive oxygen derivatives from PMNs impair T lymphocyte proliferative responses to the E. histolytica mitogen. The Authors suggest that one of the mechanisms by which circulating immune complexes present in the sera of patients with amoebiasis may interfere with T cell-mediated immune responses, is through their binding to the surface of the C3+, Fc IgG+ cells with subsequent stimulation of the PMN oxidative metabolism.

Lipopolysaccharide (LPS) of Salmonella typhi has been analyzed by immunoblotting with pooled sera from typhoid patients. Pooled typhoid sera have recognized all the antigenic determinants of S. typhi LPS, giving a strong reaction with the repeating units on the O-side chains as well as with the core region. Cross-reacting antigens have been observed with the LPS of S. typhimurium and S. enteritidis, while no heterologous reactions were seen with the LPS of E. coli strains.