Oral administration of preformed specific antibodies is an attractive approach against infections of the digestive system in humans and animals in times of increasing antibiotic resistances. Previous studies showed a positive effect of egg yolk IgY antibodies on bacterial intoxications in animals and humans. Immunization of chickens with specific antigens offers the possibility to create various forms of antibodies. Research shows that orally applied IgY’s isolated from egg yolks can passively cure or prevent diseases of the digestive system. The use of these alternative therapeutic drugs provides further advantages: (1) The production of IgY’s is a non-invasive alternative to current methods; (2) The keeping of chickens is inexpensive; (3) The animals are easy to handle; (4) It avoids repetitive bleeding of laboratory animals; (5) It is also very cost effective regarding the high IgY concentration within the egg yolk. Novel targets of these antigen specific antibodies are Helicobacter pylori and also molecules involved in signaling pathways in gastric cancer. Furthermore, also dental caries causing bacteria like Streptococcus mutans or opportunistic Pseudomonas aeruginosa in cystic fibrosis patients are possible targets. Therefore, IgY’s included in food for human consumption may be able to prevent or cure human diseases.

The specificities of autoantibodies directed against the acetylcholine receptor (AChR) for embryonic and adult muscle AChR were studied in 22 mothers with myasthenia gravis (MG) and in their newborns using human fetus and normal adult muscle AChR preparations. 12 mothers had transmitted MG to their neonates with, in three cases, antenatal injury. A clear correlation was found between occurrence of neonatal MG (NMG) and the high overall level of antiAChR antibodies (embryonic or adult muscle AChR). However, a strong correlation was also found between occurrence of NMG and the ratio of anti-embryonic AChR to anti-adult muscle (Te/Ta) AChR antibodies (P < 0.0002). Taken together, these data suggest that autoantibodies directed against the embryonic form of the AChR could play a predominant role in the pathogenesis of NMG. Paradoxically, the three cases with antenatal injury presumably the most severe form of NMG, were not associated with high Te/Ta. At the clinical level, these observations could prove helpful in the prediction of transmission of NMG. (J. Clin. Invest. 1994. 94:555-559.)

High anti-fetal/anti-adult muscle anti-acetylcholine receptor (AChR) antibody (Ab) titer ratio is predictive of the occurrence of neonatal myasthenia gravis in a first child. The aim of the present study was to determine whether the ratio between the levels of antibodies is an intrinsic property of the mother's sera or varies with physiologic status such as pregnancy. We performed a longitudinal study of the levels of Ab directed against both fetal and adult AChRs and the ratio between them in 11 mothers with myasthenia gravis (MG). Sera were taken during, before, and after pregnancy. Absolute levels of Ab varied considerably during the time of observation as indicated by analyzing the maximum change between any two sample times during the study (adult mean percentage change 45.9 +/- 26.4; fetal 42.51 +/- 22.05). In contrast to this, the anti-fetal/anti-adult muscle AChR Ab titer ratio was much less variable (mean percentage change 16.66 +/- 10.11; p < 0.0033). The levels of the two Ab types yielded a correlation of 0.918, consistent with the stability of the ratio between them. This stability of ratio has practical value in the management of pregnancy and infant care in mothers with MG because the ratio at any time, before or during pregnancy, will predict whether the child will contract neonatal MG. We determined this for the first child, but further studies are necessary to establish if this remains true for subsequent pregnancies.

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Summary Sera from young cattle hyperimmunized with inactivated oil‐adjuvant Aujeszky's (AVa) or IBR vaccine and developing high titres of homologous antibodies (1: 256–1: 4,096) neutralized also the heterologous virus. Mutual cross‐neutralization activity was recorded in nasal secretions from calves at the time of the highest titres of serum antibodies. Susceptible calves with no antibodies against IBR virus produced, after vaccination and re‐vaccination with AVa or IBR vaccine, antibodies at medium or high titres against only the homologous virus; they responded anamnestically however to the application of heterologous vaccine as if they were immunologically stimulated. Sera from animals naturally infected with IBR virus neutralized AVi even at low titres of homologous antibodies. In natural infection IBR seropositive calves responded to the application of AVa by an increase in IBR antibodies, and to IBR vaccine by developing, in addition to an increase of homologous antibodies, neutralizing activity against AVi. Conjugates prepared from the sera of cattle hyperimmunized with AVa or IBR vaccine visualized in the infected cell cultures both homologous and heterologous viruses. Sera of pigs with high titres of antibodies against AVi did not neutralize IBR virus and rabbits immunized with IBR vaccine remained fully sensitive to AVi infection. The possibility of cross‐protection of cattle immune to Aujeszky's disease, or IBR immune cattle against infection with heterologous virus is discussed. Zusammenfassung Untersuchungen über immunologische Beziehungen zwischen Infektiösem Bovinem Rhinotracheitis‐Virus (IBR) und dem Virus der Aujeszkyschen Krankheit mit Kälbern, Schweinen und Kaninchen Seren von Jungrindern, die mit inaktivierter Aujeszky‐ oder IBR‐Öladjuvansvakzine vakziniert worden waren, neutralisierten im Falle hoher homologer Antikörpertiter (1: 256–1: 4096) auch das heterologe Virus. Kreuzneutralisierende Aktivitäten konnten auch in Nasensekreten von Kälbern nachgewiesen werden, die zum Zeitpunkt des Auftretens von Höchsttitern der Serumantikörper entnommen wurden. Empfängliche Kälber ohne IBR‐Virusantikörper produzierten nach Vakzinierung und Revakzinierung mit Aujeszky‐ oder IBR‐Vakzinen nur Antikörper gegen das homologe Virus. Sie zeigten jedoch eine anamnestische Reaktion nach Applikation der jeweils heterologen Vakzine. Seren von natürlich mit IBR‐Virus infizierten Tieren neutralisierten Aujeszkyvirus sogar dann wenn nur niedrige homologe Antikörpertiter vorlagen. Natürlich mit IBR‐Virus infizierte seropositive Kälber reagierten nach Impfung mit Aujeszky‐Vakzinen mit einem Anstieg der IBR‐Virusantikörpertiter. Nach Applikation der IBR‐Vakzine wurde neben dem Anstieg homologer Antikörpertiter auch die Entwicklung von Antikörpern gegen Aujeszkyvirus beobachtet. Mit Immunfluoreszenz‐Konjugaten, die von Rinderseren hergestellt wurden, deren Spender zuvor mit Aujeszky‐ oder IBR‐Vakzine hyperimmunisiert worden waren, ließen sich in infizierten Zellkulturen sowohl homologe als auch heterologe Viren nachweisen...