Naslov
Development of Ig secreting cells in mMT/mMT BALB/c mice

Autori
Hasan, Milena ; Krmpotić, Astrid ; Čičin-Šain, Luka ; Bralić, Marina ; Polić, Bojan ; Jonjić, Stipan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Annual Meeting of the Croatian Immunological Society / Rabatić, Sabina - Zagreb : Hrvatsko imunološko društvo, 1999, 1-1

Skup
Annual Meeting of the Croatian Immunological Society

Mjesto i datum
Zagreb, Hrvatska, 25.11.1999

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
mMT/mMT mutation; BALB/c mice; B-cell development

Sažetak
The m chain together with the surrogate light chain (lambda 5 + V pre-B) forms the pre-B cell receptor (pre-BCR)on the surface of pre-B cells before the assembly of the complete Ig molecule. The pre-BCR expression on the pre-B cells and formation of the surface IgM molecules, after the light chain rearragement on immature B cells are key checkpoints in the development of mature B lymphocytes. Ig class switch and the subsequent expresion of other Ig classes occurs only in mature B cells, after they have undergone germinal center reaction in the secondary lymphoid organs. Therefore, the disruption of the membrane exone of Ig m chain genes blocks the B cell development at the pre-B stage. C57BL/6 mice homozygous for this mutation (mMT/mMT C57BL/6)are unable to generate immature and mature B cells and subsequently lack Ig in their sera (Kitamura et al., Nature, 350, 423-426, 1991.). We have backcrossed the mMT mutation onto BALB/c mice. The offspring homozygous for the mutation (mMT/mMT BALB/c) were tested for the presence of immunoglobulins. Surprisingly, although unable to produce IgM, the mMT/mMT BALB/c mice had high levels of IgG in their sera. Further experiments showed the presence of different Ig classes and subclasses. Despite the IgG presence mMT/mMT BALB/c mice could not generate a specific antibody response. The spleen ad lymph node architecture of mMT/mMT C57BL/6 and mMT/mMT BALB/c mice was similar. Both strains lacked lymphatic follicles in the spleen and lymph nodes, yet anti mouse Ig-POD labeled antibodies stained cells scattered throughout the lymphatic organs of mMT/mMT BALB/c mice. In addition, the Ig positive cells were found also in the lamina propria of the intestinal mucosa. The presence of serum Ig and Ig positive cells strongly suggests that the developmental block at the pre-B cell stage is leaky in mMT/mMT BALB/c mice. The cause of this leakage could be attributed to occasional early class switch events. Our next aim is to clarify the underlaying mechanism of this phenotype.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti, Kliničke medicinske znanosti

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