trouble with making and gate
When you turn on the upper switch, current passes directly from the base to the emitter of transistor T2, lighting the LED. In this mode, the transistor is functioning as a diode.

When you turn on the lower switch, the same thing would happen with T1, except that T2 is not passing any current, keeping the LED from lighting.

If you put the LED in series with the collector of T1, you'll get the effect you're looking for &mdash; but now you also need additional resistors to limit the base current into the transistors:







simulate this circuit &ndash; Schematic created using CircuitLab