The Hoeppli phenomenon in schistosomiasis japonica: historical findings and additional investigation in bovines

The present paper deals with a buried knowledge of the early findings of the Hoeppli phenomenon in cattle infected with Schistosoma japonicum together with a revised list of bovines and other mammalian species in which this phenomenon has been found. It was noted that the percentage of the mature-egg granulomas with positive Hoeppli phenomena varied with the species of bovines, ie, higher positive percentage in the more susceptible cattle than in the less susceptible buffalos. The radiating filaments in fringes of the phenomenon were also stronger in cattle than in buffalos.

Vaccination against schistosomiasis in mice with killed schistosomula without adjuvant

Attempts to develop a killed vaccine against schistosomiasis have generally resulted in failure. There are two recent reports, but unfortunately, harsh adjuvants were used in conjunction with the antigenic materials. In our laboratory, a killed vaccine was developed by freezing (-196 degrees C) and thawing the schistosomula of S. mansoni. The use of such a preparation without adjuvant was effective in vaccinating mice. A worm reduction of 36.4-41.1% was achieved by one vaccinating injection, a 60.2% worm reduction by 3 injections, and a 63.7-66.0% reduction by 5 injections. The sequence of the development and the expression of the immune reactions were similar to those previously found in hosts immunized with highly X-irradiated schistosome organisms. Delayed hypersensitivity was demonstrated in histological sections of the skin in the challenged mice after one vaccination, showing that an adjuvant was not necessary to initiate the induction of cellular immunity.

Vaccination of bovines against schistosomiasis japonica with highly irradiated schistosomula in China

Vaccination of Chinese bovines (cattle and buffaloes) against schistosomiasis japonica with 36 kR gamma-irradiated schistosomula was done for laboratory challenge and for field trials in China. Altogether, 61 bovines were used. All experimental animals were vaccinated 2-3 times with 10,000 irradiated schistosomula per time. For the laboratory challenge, all experimental and control cattle were challenged with 500 normal cercariae and each buffalo, with 2,000 cercariae. The laboratory-challenged bovines were killed after 54-57 days of challenge; the bovines for the field trial in the lightly endemic area, after 5 months in the field; and the bovines for the field trial in the heavily endemic area, after 58-63 days. When the animals were killed, the number of mature worms in the vaccinated (experimental) and non-vaccinated (control) animals was recorded and the percentage of worm reduction in each group was calculated. The first group, consisting of three vaccinated and three non-vaccinated cattle, was given a laboratory challenge; the worm reduction was 71.6%. The second group, consisting of two vaccinated and three non-vaccinated buffaloes, was also given a laboratory challenge; the worm reduction was 74.4%. The third group, consisting of seven vaccinated and eight non-vaccinated buffaloes, was utilized in a field trial in a lightly endemic area; the worm reduction was 75.6%. The fourth group, consisting of eight vaccinated and nine non-vaccinated cattle, and the fifth group, consisting of nine vaccinated and nine non-vaccinated buffaloes, were pastured in a heavily endemic area. The worm reduction was 65.1% in the fourth group and 75.7% in the fifth group.(ABSTRACT TRUNCATED AT 250 WORDS)

Vaccination against bovine schistosomiasis japonica with highly X-irradiated schistosomula

Cercariae of the Chinese mainland strain of Schistosoma japonicum were used. Eighteen cattle, divided into six groups of three each, were immunized with schistosomula transformed from cercariae exposed to three different doses of X-irradiation (24, 36, and 48 kR). The immunization was given either once, twice, or thrice, and the number of immunizing schistosomula was 10,000 or more in each immunization. The immunized cattle were challenged with 500 normal cercariae. Five native cattle were similarly infected with normal cercariae as controls. All cattle were killed 32-33 days after challenge or infection, and the worms were obtained by perfusion. The mean worm reduction in the 18 experimental animals varied from 42.1 to 96.0%. The mean percent worm reduction of the six experimental groups varied from 54.8 to 87.1. The reduction was greater with increasing numbers of immunizations, and was higher in the groups immunized with schistosomula exposed to 36 kR than in those exposed to 24 or 48 kR. Statistical analyses showed that all immunized groups yielded significantly fewer worms than controls. However, the three doses of X-irradiation (24, 36, and 48 kR) had no significant effect for a fixed number of immunizations (1, 2, or 3). The means for both two and three immunizations were significantly different from the mean for one immunization, although they were not significantly different from each other.

Histopathological study of the attrition of challenge cercariae of Schistosoma mansoni in the skin of mice immunized by chronic infection and by use of highly X-irradiated cercariae

To find direct evidence for the sites of death of newly transformed schistosomula of Schistosoma mansoni in the skin of challenged immunized hosts, a histopathological study of the skin of chronically infected mice and of highly X-irradiated cercaria-immunized mice was made at different post-challenge times. Attrition of infecting organisms in naive mice was used as a control. In general, three main kinds of schistosomular attrition were observed: (1) in the granulocytic exudates in the epidermis, (2) in the granulocytic aggregates in the subcutaneous tissue, and (3) in the granuloma-like foci in the subcutaneous tissue. Schistosomula killed by the epidermal granulocytic exudates and by the subcutaneous granuloma-like foci occurred in all three groups of mice, but the schistosomula killed by the subcutaneous granulocytic aggregates were found only in the highly X-irradiated cercaria-immunized animals. Schistosomula killed by the epidermal granulocytic exudates were encountered occasionally in the challenged naive mice but more frequently in both the challenged chronically infected mice and the challenged highly X-irradiated cercaria-immunized mice. The number of subcutaneous granuloma-like foci was greater in the challenged mice immunized with highly X-irradiated cercariae than in the challenged naive mice or the challenged chronically infected mice. Another differentiating character among the three groups of mice was that in the highly X-irradiated cercaria-immunized group, the subcutaneous granuloma-like foci appeared on day 3 after the challenge, but on day 5 in the naive and chronically infected groups. The results clearly indicate that skin is an important site for the attrition of the challenged cercariae in the highly X-irradiated cercaria-immunized mice, and that immunity in the chronically infected and X-irradiated cercaria-immunized mice occurs by different mechanisms.

Schistosoma mansoni: is acquired immunity induced by highly x-irradiated cercariae dependent on the size of the challenging dose?

A high degree of immunity, as shown by a 91% reduction of the number of worms recovered was found in five groups of mice that were immunized five times with highly X-irradiated cercariae and then challenged with 10, 20, 50, 100, or 500 normal Schistosoma mansoni cercariae. The results indicated that there were no significant differences in worm reduction in immunized mice challenged with different numbers of cercariae; consequently the immunity induced by this immunization method did not appear to be challenge-dose-dependent. However, the results also showed that when immunized mice were challenged with 500, 100, 50, 20, and 10 cercariae, 0, 13, 26, 56, and 68%, respectively, of the experimental animals were free of worms. Thus, the percentage of worm-negative cases increased as the number of challenge cercariae decreased. When viewed in this manner, the acquired immunity may be considered challenge-dose-dependent as well. If this method of vaccination is used for schistosomiasis control, we may anticipate that in both hypo- and hyperendemic areas, the intensity of infection and the severity of the disease will be reduced owing to a reduction in worms burdens, and in hypoendemic areas, there will be a number of worm-free cases.

Immunoglobulins and complement in the skin of rhesus monkeys immunized with x-irradiated cercariae of Schistosoma japonicum

Skin sections of rhesus monkeys immunized with X-irradiated Schistosoma japonicum cercariae were stained by an unlabeled antibody enzyme method for the detection of IgG, IgM, IgA, IgE, and C3. While all of them could be found in the skin lesions, their distribution patterns varied with time and reactions. In whealing reaginic reactions, IgE appeared prominent, having an affinity to the mast cells. In Arthus-like reactions, IgG was predominant. IgG complexes were found on the schistosomula, on the walls of blood vessels, and in granulocytes near the schistosomula. In the late stage of Arthus-like reactions and in delayed hypersensitive reactions, IgA was predominant in granulocytes, mononuclear cells, and macrophages. Characteristics of each immunoglobulin pattern seemed to reflect its function in the effector mechanism. It may be speculated that these immunoglobulins and C3, together with effector cells, synergistically and sequentially destroy schistosomula in the skin.

Eosinophils as effector cells in the destruction of Schistosoma mansoni eggs in granulomas

Histopathological sections of wedge-biopsied liver and surgically removed gallbladder of a schistosomiasis mansoni patient were studied for the eosinophil-mediated destruction of eggs in granulomas. Apparent degranulation of eosinophils on the eggs in the granulomas and concomittant deterioration of miracidia were observed. It was construed that granule-associated enzymes may be released upon the degranulation of eosinophils, pass through the micropores of the egg shell and cause death of the miracidium inside the egg.

Evaluation of lung recovery assay for schistosomula in mice immunized with x-irradiated cercariae of Schistosoma mansoni

The lung recovery assay for schistosomula has recently been used as a rapid method for measuring the state of immunity of a challenged animal. Its merit rests on the fact that the peak day of schistosomular recovery in the lungs of both normal and immune hosts falls on the same day and the degree of immunity can be measured by the percent of schistosomular recovery on this particular day. An evaluation of this method for mice immunized with highly X-irradiated cercariae of Schistosoma mansoni was made. The results indicate that in the immunized mice the peak day for the schistosomular recovery was delayed and the number of schistosomula recovered on the peak day was decreased. The delay of the peak day was increased by the degree of host immunity, so its identification for a host of an unknown immunologic status was not a simple matter. In addition, this method measured only the immune effect which took place in the skin and on prepeak days in the lungs. It was not as competent as the conventional liver perfusion method which measures the total result of the immune effect of the skin, lungs, and liver. Our conclusion is that for measuring the immunizing effect of irradiated cercariae, the lung recovery method is not suitable for the determination of the state of immunity induced.

Immunoglobulin E, mast cells, and eosinophils in the skin of rhesus monkeys immunized with x-irradiated cercariae of Schistosoma japonicum

Immunoglobulin E (IgE), mast cells, and eosinophils in the skin of rhesus monkeys immunized with highly X-irradiated cercariae of Schistosoma japonicum were studied. IgE was stained by the unlabeled antibody enzyme method and was found on mast cells. Before challenge, mast cells were found only in the dermis. Immediately after the challenge, mast cells were found in both the dermis and epidermis and many of them were degranulated. Soon after, margination and emigration of granulocytes, predominantly eosinophils, occurred along the blood capillaries in the dermis. Gradulally, preivascular infiltration of eosinophils was seen in the dermis and migration of eosinophils from the dermis into the epidermis appeared, resulting in the formation of minute eosinophilic abscesses in the epidermis. In addition, the IgE was found as a thin coat on the integument of the schistosomula. Deteriorated schistosomula were seen amid the eosinophilic abscesses in the epidermis and in eosinophilic infiltrations in the dermis. The present findings suggest the possibility that the reaction of IgE, mast cells, and eosinophils were integrated into one immunological effect, namely the schistosomulicidal action.

Immunization against schistosome infection in rhesus monkeys with living worms by intraperitoneal injection

Immunization was performed against Schistosoma mansoni or S. japonicum infection in rhesus monkeys either with living schistosomula and young adult worms or with only schistosomula by intra-peritoneal injection. Each monkey was immunized four or more times and subsequently challenged. A significant degree of resistance against the challenge was produced. The injected worms lived in the peritoneal cavity for a short period, then died and disintegrated therein, thus obviating their inhabiting the circulatory system. The functional antigens were evidently derived from the metabolic products of the immunizing living schistosomes in the peritoneal cavity.

The results of the present experiment indicate that the main immune mechanism induced by the intraperitoneal injection of living schistosomula and young adult worms is that which inhibits the development of the late stage of schistosomula and the early stage of adults which have originated from the challenge infection. This immune mechanism may be induced by the functional antigens either from both the schistosomula and adult worms or from the schistosomula alone.